CRANBERRY  DISEASES 


A  Thesis  submitted  to  the   Faculty  of  Graduate 
Studies  of  the  George  Washington  University 
in  part  satisfaction  of  the  requirements 
for  the  degree  of  Doctor  of  Phi- 
losophy, June,  1906. 


BY 

CORNELIUS  LOTT  SHEAR,  B.  S.,  A.  M.,  Ph.  D 


WASHINGTON,   D.   C. 
1907 


This  thesis  was  defended  publicly  ,.' 

r 

By  CORNELIUS  LOTT  SHEAR,  B.  S.,  A.  M.,  University  of 
Nebraska,  in  doctorate  disputation,  Monday,  May  28, 
1906. 

Before  FRANK  H.  KNOWLTON,  Ph.  D. 

JOHN  R.  MOHLER,  A.  M.,  V.  M.  D. 
MERTON  B.  WAITE,  B.  S. 

Professor  ALBERT  MANN,  Ph.  D.,  presiding. 


But.  •nV*Bur*aa   ot  PlSnt'lruiuStVy,   U.   S.   Dept.   of  Agriculture. 


PLATE  I 


CRANBERRY  SCALD. 


A.    HOEN    4    CO.,    LITH. 


U.  S.  DEPARTMENT   OF   AGRICULTURE. 

BUREAU  OF  PLANT  INDUSTRY— BULLETIN  NO.  110. 

B.  T.  GALLOWAY,  Ckitf  of  Bureau. 


CRANBERRY  DISEASES 


BY 


C.  L.  SHEAR, 

// 

PATHOLOGIST  IN  CHARGE  OF  INVESTIGATIONS  OF 
DISEASES  OF  SMALL  FRUITS. 


ISSUED  OCTOBER  10,  1907. 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 
1907. 


BUREAU  OF  PLANT  INDUSTRY. 

Pathologist  and  Physiologist,  and  jOhicf  of  Bureau,  Beverly  T.  Galloway. 

Pathologist  and  Physiologist,  and  Assistant  Chief  of  Bureau,  Albert  F.  Woods. 

Laboratory  of  Plant  Pathology,  Erwin  F.  Smith,  Pathologist  in  Charge. 

Investigations  of  Diseases  of  Fruits,  Merton  B.  Waite,  Pathologist  in  Charge. 

Laboratory  of  Forest  Pathology,  Haven  Metcalf,  Pathologist  in  Charge. 

Plant  Life  History  Investigations,  Walter  T.  Swingle,  Physiologist  in  Charge. 

Cotton  and  Tobacco  Breeding  Investigations,  Archibald  D.  Shamel,  Physiologist  in  Charge. 

Corn  Investigations,  Charles  P.  Hartley,  Physiologist  in  Charge. 

Alkali  and  Drought  Resistant  Plant  Breeding  Investigations,  Thomas  H.  Kearney,  Physi- 
ologist in  Charge. 

Soil  Bacteriology  and  Water  Purification  Investigations,  Karl  F.  Kellerman,  Physiologist 
in  Charge. 

Bionomic  Investigations  of  Tropical  and  Subtropical  Plants,  Orator  F.  Cook,  Bionomist  in 
Charge. 

Drug  and  Poisonous  Plant  Investigations  and  Tea  Culture  Investigations,  Rodney  II. 
True,  Physiologist  in  Charge. 

Physical  Laboratory,  Lyman  J.  Briggs,  Physicist  in  Charge. 

Crop  Technology  Investigations,  Nathan  A.  Cobb,  Expert  in  Charge. 

Taxonomie  Investigations,  Frederick  V.  Coville,  Botanist  in  Charge. 

Farm  Management  Investigations,  William  J.  Spillman,  Agriculturist  in  Charge. 

Grain  Investigations,  Mark  A.  Carleton,  Cerealist  in  Charge. 

Arlington  Experimental  Farm,  Lee  C.  Corbett,  Horticulturist  in  Charge. 

Sugar-Beet  Investigations,  Charles  O.  Townsend,  Pathologist  in  Charge. 

Western  Agricultural  Extension  Investigations,  Carl  S.  Scofteld,  Agriculturist  in  Charge. 

Dry  Land  Agriculture  Investigations,  E.  Channing  Chilcott,  Agriculturist  in  Charge. 

Pomological  Collections,  Gustavus  B.  Brackett,  Pomologist  in  Charge. 

Field  Investigations  in  Pomology,  William  A.  Taylor  and  G.  Harold  Powell,  Pomologists 
in  Charge. 

Experimental  Gardens  and  Grounds,  Edward  M.  Byrnes,  Superintendent. 

Vegetable  Testing  Gardens,  William  W.  Tracy,  sr.,  Superintendent. 

Seed  and  Plant  Introduction,  David  Fairchild,  Agricultural  Explorer  in  Charge. 

Forage  Crop  Investigations,  Charles  V.  Piper,  Agrostologist  in  Charge. 

Seed  Laboratory,  Edgar  Brown,  Botanist  in  Charge. 

Grain  Standardization,  John  D.  Shanahan,  Expert  in  Charge. 

Subtropical  Laboratory  and  Garden,  Miami,  Fla.,  Ernst  A.  Bessey,  Pathologist  in  Charge. 

Plant  Introduction  Garden,  Chico,  Cal.,  August  Mayer,  Expert  in  Charge. 

South  Texas  Garden,  Brownsville,  Tex.,  Edward  C.  Green,  Pomologist  in  Charge. 

Cotton  Culture  Farms,  Seaman  A.  Knapp,  Lake  Charles,  La.,  Special  Agent  in  Charge. 


Editor,  J.  E.  Rockwell. 
Chief  Clerk,  James  E.  Jones. 


INVESTIGATIONS  OF  DISEASES  OF  FRUITS. 
SCIENTIFIC  STAFF. 

M.  B.  Waite,  Pathologist  in  Charge. 

P.  J.  O'Gara,  W.  S.  Ballard,  and  F.  W.  Faurot,  Scientific  Assistants. 

C.  L.  Shear,  Pathologist  in  Charge  of  Investigations  of  Diseases  of  Small  Fruits. 
George  F.  Miles,  Lon  A.  Hawkins,  and  Mrs.  Anna  K.  Wood,  Scientific  Assistants. 

W.  M.  Scott,  Pathologist  in  Charge  of  Orchard  Spraying  Demonstration  Work. 
James  B.  Ilorer  and  T.  W.  Ayres,  Scientific  Assistants. 
110 

2 


LETTER  OF  TRANSMITTAL 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  PLANT  INDUSTRY, 

OFFICE  OF  THE  CHIEF, 
Washington,  D.  C.,  April  26,  1907. 

SIR  :  I  have  the  honor  to  transmit  herewith,  and  to  recommend  for 
publication  as  Bulletin  No.  110  of  the  series  of  this  Bureau,  the 
accompanying  technical  paper  entitled  "  Cranberry  Diseases,"  by 
Dr.  C.  L.  Shear,  Pathologist  in  Charge  of  Investigations  of  Dis- 
eases of  Small  Fruits. 

This  paper  contains  the  first  full  account  of  the  fungous  parasites 
of  the  cranberry  and  the  diseases  they  produce.  It  also  gives  suc- 
cessful methods  of  preventing  the  diseases. 

The    illustrations   which    accompany   this   paper   are   considered 
essential  to  a  full  understanding  of  the  text. 
Respectfully, 

B.  T.  GALLOWAY, 

Chief  of  Bureau. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 
110 


239382 


CONTENTS. 


Page. 

Introduction ! 9 

Previous   investigations ' 10 

The  most  serious  diseases 12 

Blast  _-  12 

Scald 13 

The  fungus  (Guignardia  vaccinii  Shear)  causing  blast  and  scald 14 

Pycnidial   form 14 

Ascogenous  form 15 

Cultures  of  Guignardia  vaccinii 16 

Pycnidial  form 16 

Ascogenous  form 17 

Conditions  or  factors  determining  the  production  of  the  ascogenous 

form 19 

Dormant  condition  of  the  fungus 21 

Time  and  manner  of  infection 22 

Treatment 24 

Applications  to  the  soil 24 

Improving  the  condition  of  the  plants 24 

Selection  of  resistant  varieties 25 

Application  of  fungicides 25 

Rot 26 

The  fungus  (Acanthorhynchus  vaccinii  Shear)  causing  the  rot 27 

Ascogenous  form 27 

Appressoria 27 

Relationship  of  the  fungus 28 

Cultures  of  the  fungus 29 

Treatment 30 

Anthracnose 30 

The  fungus    (Glomerella  rufomaculans  vaccinii  Shear)   causing  an- 

thracnose 31 

Conidial  form 31 

Ascogenous  form 31 

Appressoria,  or  chlamydospores 32 

Cultures  of  Glomerella  rufomaculans  vaccinii 32 

Factors  determining  the  production  of  the  ascogenous  fructifica- 
tion   33 

Relationship  of  the  fungus 33 

Dormant  condition  of  the  fungus 34 

Treatment 35 

Hypertrophy 35 

The  fungus  (Exobasidiwn  oxycocci  Rostr.)  causing  hypertrophy 36 

Relationship  to  other  Exobasidii —  36 

Treatment... , 37 

110 

5 


6 


CONTENTS, 


!  *   :  •     •  '«?  i     .*  •*£'  '  /  Page. 

Less  important  diseases  _'.i^ii_-J__lil 37 

Fungi  attacking  the  fruit 37 

Synchytrium  vaccinii  Thomas 37 

Pestalozzia  guepini  vaccinii  Shear 38 

Pestalozzia  </uepini  Desm 39 

Helminth  osporium   inaequalis  Shear 39 

Gloeosporium  minus  Shear k 40 

Sporonema  oxycocci  Shear 41 

Arachniotus  trachyspermus  Shear 41 

Septoria  longispora  Shear 42 

Sphacroiicma  pornorum  Shear '. 42 

.  Phyllosticta  putrefaciens  Shear 43 

Anthostomella  destruens  Shear 43 

Penicillium  glaucum  Link 43 

Leptothyrium  pomi  (Mont)  Sacc.? 44 

Fungi  occurring  on  the  leaves  or  stems 44 

Venturia  compacta  Peck 45 

Sclerotinia  oxycoccl  Wor?_^ 45 

Discosia  artocreas.  (Tode)  Fr : 40 

PlagiorhaMus  oxycocci  Shear 40 

'Sporon&tna  pulvinatum  Shear 40 

Rhabdospora  oxycocci  Shear 47 

Leptothyrium  oxycoccl   Shear 1  47 

Ceuthospora  (?)   lunata  Shear 47 

Valsa  delicatula  C.  &  E 48 

Cladosporium  oxycocci  Shear 48 

Plectrothrix  globosa  Shear 48 

Chondrioderma  simplex  Schroet 48 

Epicoccum    49 

Diplodia 49 

Chaetomium 49 

Oospora 49 

Macrosporium 49 

Preventive  and  remedial  measures _• —  49 

Regulation  of  the  water  supply 49 

Destruction  of  diseased  vines 50 

Selection  and  breeding  of  resistant  plants _ —  50 

Application  of  fungicides 50 

Bordeaux  mixture 51 

Preparation  and  application 52 

Cost  of  spraying 53 

Summary  ^ 

Bibliography  of  cranberry  diseases 55 

Description  of  plates 58 

Index 61 

110 


LLUSTRATIONS. 


Page. 
PLATE  I.  Cranberry  scald,  showing  different  stages  in  the  progress  of  the 

disease Frontispiece. 

II.  Fungous  parasites  of  the  cranberry.     Figs,  1  to  14. — Guignardia 

vaccinii.    Fig.  15. — Pestalozzia  guepini  vaccinii 60 

III.  Fungous  parasites  of  the  cranberry.     Figs.  1  to  9. — Glomerella 

ritfoniaculans     vaccinii.     Figs.     10     and     11. — Gloeosporium 
minus.     Figs.  12  to  22. — Acanthorhynchus  vaccinii GO 

IV.  Fungous  parasites  of  the  cranberry.     Figs.   1  to   7. — Venturia 

compacta.     Figs.  8  to  11. — Anthostomella  destruens.     Figs.  12 
to    14. — Septoria    longispora.     Figs.    15    to    17. — Synchytrium 

vaccinii.     Figs.  18  to  22. — Arachniotus  trachyspermus 60 

V.  Less  important  cranberry  fungi.  Fig.  1. — Sphaeroncma  ponio- 
rum.  Figs.  2  and  3. — Plagiorhabdus  oxycocci.  Figs  4  to 
9. — Helminthosporium  inaequalis.  Fig.  10. — Phylloitticta  pu- 
trefaciens.  Pigs.  11  and  12. — Ceuthospora  (?)  lunata.  Figs. 
13  to  15. — Lcptothyrium  poim  (V).  Fig.  16. — Fungous  spores 
associated  with  Leptotliyriwn  pomi  (?).  Figs.  17  to  20. — 
Sporoncnia  c.vi/coccL  Figs.  21  to  24. — Rhabdospora  oxycocci. 
Figs.  25  to  28.—8poronema  puivinatum.  Figs.  29  to  33. — Lep- 

totliyrium  oxycocci 60 

VI.  Cranberries  destroyed  by  blast  and  scald 60 

VII.  Cranberry    Exobasidii.     A    and    B. — Etrobasidium    vaccinii.     C 

and  D. — Exobasidium  oxycocci 60 

110 


B.  P.  I.— 286. 

CRANBERRY  DISEASES. 


INTRODUCTION. 

The  American  cranberry  (Vaccinium  macrocarpum)  has  been  in 
cultivation  for  seventy-five  years  or  more.  The  wild  plant  in  its 
native  habitat  does  not  appear  to  be  affected  to  any  very  noticeable 
degree  by  fungous  parasites.  Up  to  the  present  time  only  five  species 
of  fungi,  according  to  the  published  host  indices,  have  been  reported 
as  occurring  upon  this  plant.  It  is  generally  the  case,  however,"  that 
the  longer  a  plant  is  in  cultivation  and  the  greater  the  area  covered 
by  it  the  more  numerous  and  serious  are  its  parasites,  since  the  con- 
ditions and  opportunities  for  their  development  and  distribution  be- 
come much  more  favorable.  This  is  true  of  the  cranberry.  At  the 
same  time,  this  plant  by  selection,  cultivation,  and  growth  under 
rather  abnormal  conditions  has  apparently  become  somewhat  weak- 
ened and  more  susceptible  to  disease. 

The  cranberry  is  distributed  from  Newfoundland  southward 
through  the  Alleghenies  to  North  Carolina  and  westward  into  Wis- 
consin. It  is  also  cultivated  in  a  few  localities  on  the  Pacific  coast, 
in  Oregon  and  Washington.  The  native  cranberry  of  that  region  is 
regarded  by  some  botanists  as  a  variety  of  Vaccinium  oxy coccus.'1  (°) 

The  diseases  of  the  cranberry  are  most  serious  in  the  southern  sec- 
tions of  its  area  of  cultivation.  The  losses  from  the  various  maladies 
are  heaviest  in  New  Jersey  and  decrease  as  one  proceeds  northward 
through  Long  Island,  Connecticut,  and  Massachusetts,  being  least  of 
all  in. the  bogs  of  Nova  Scotia.  There  is  also  comparatively  small 
loss  from  disease  at  present  in  Wisconsin  and  on  the  Pacific  coast. 
The  annual  crop  of  the  United  States  approximates  1,000,000  bushels, 
valued  at  about  $2,000,000.  The  loss  from  disease  is  estimated  to 
average  about  10  per  cent,  or  $200,000  each  year.  From  a  careful 
study  of  the  matter  is  seems  probable  that  the  climatic  conditions  are 
chiefly  responsible  for  the  greater  amount  of  loss  in  the  southern 
localities.  The  long,  hot  summers  of  the  southern  region  seem  to 
be  unfavorable  to  the  production  of  the  most  hardy  cranberry  plants 

o  The  serial  numbers  used  in  this  paper  refer  to  the  bibliography  which  will  be 
found  on  pages  55  to  57. 

3525— No.  110—07  M 2 

9 


10  CRANBERRY   DISEASES. 

and  at  the  same  time  most  favorable  for  the  development  of  the  vari- 
ous parasitic  fungi  which  attack  them. 

Several  serious  diseases  have  been  found  to  be  prevalent.  They  have 
nearly  all,  however,  been  heretofore  included  under  one  name  by 
cranberry  growers.  All  softening  of  the  fruit,  accompanied  by  more 
or  less  discoloration,  has  been  called  "  scald  "  or  "  rot."  This  was 
quite  natural,  as  the .  differences  in  the  appearance  of  fruit  attacked 
by  the  different  parasites  are  so  slight  that  it  is  difficult  to  distinguish 
between  them  by  external  examination. 

There  is  no  accurate  record,  so  far  as  we  have  been  able  to  discover, 
as  to  when  the  cranberry  diseases  first  became  sufficiently  serious  to 
cause  much  loss.  Mr.  J.  J.  White  read  a  letter  before  the  Cranberry 
Growers'  Association  in  1873  showing  that  the  scald  was  known 
twenty  years  earlier,  i.  e.,  1853.  The  diseases  have  probably  spread 
more  or  less  gradually  as  the  fruit  has  become  more  widely  cultivated. 

PREVIOUS  INVESTIGATIONS. 

Cranberry  scald  was  a  frequent  subject  of  discussion  at  the  early 
meetings  of  the  New  Jersey  Cranberry  Growers'  Association,2  which 
was  organized  in  1869  and  is  now  called  the  American  Cranberry 
Growers'  Association. 

In  1874  Dr.  Thomas  Taylor,  Microscopist  of  the  Department  of 
Agriculture,  was  sent  by  the  Commissioner  of  Agriculture,  at  the 
request  of  the  American  Cranberry  Growers'  Association,  to  investi- 
gate the  so-called  cranberry  "  scald,"  which  had  for  some  years  caused 
a  great  amount  of  loss  on  some  of  the  New  Jersey  cranberry  bogs. 
Doctor  Taylor  3  published  several  articles  giving  accounts  of  his  obser- 
vations and  studies.  He  concluded,  as  a  result  of  his  work,  that 
the  primary  cause  of  the  trouble  was  an  excess  of  acid  in  the  soil  and 
water.  He  also  believed  that  excessive  heat  and  drought  were  impor- 
tant factors,  causing  a  fermentation  to  take  place  in  the  fruit.  He 
observed  fungous  filaments  in  the  rotten  or  scalded  berries-  but  did 
not  consider  this  fact  of  much  importance. 

Taylor  5  says  (Monthly  Report,  Dept.  Agr.,  1875,  446)  :  "  I  am 
convinced  that  the  scald  and  rot,  so  called,  -of  the  berry  may  arise 
from  dissimilar  causes,  although  chemically  considered  they  are 
practically  the  same,  viz,  the  conversion  of  their  starch  into  grape 
sugar,  a  fermentable  substance  affording  a  nidus  for  the  growth  of 
fungi." 

It  will  be  seen  from  this  quotation  that  the  presence  of  a  fungus 
was  not  considered  the  cause  of  the  disease,  but  rather  a  secondary 
matter.  Taylor  believed  that  the  trouble  might  be  remedied  by 
some  application  to  the  soil  which  would  correct  its  acidity  and  pre- 
vent the  fermentation  in  the  fruit.  In  accordance  with  this  sug- 
110 


I'UKVIOUS    INVESTIGATIONS.  11 

gestion  a  considerable  variety  of  substances  ivas  tried  by  the  cran- 
berry growers,  including  lime,  copperas,  salt,  and  sulphur.  Little 
or  no  benefit,  however,  seems  to  have  been  derived  from  these  appli- 
cations, and  the  diseases  continued  to  cause  serious  loss,  varying 
somewhat  in  different  seasons  as  the  climatic  and  other  conditions 
chanced  to  be  favorable  to  their  development  or  otherwise. 

Schroeter,8  in  1879,  in  discussing  a  sclerotium  disease  of  the  fruit 
of  Vaccinium  myrtillus,  mentions  the  American  cranberry  disease 
which  had  been  described  by  Taylor  and  expressed  his  belief  that  the 
trouble  was  due  to  a  parasitic  fungus,  either  the  same  or  one  similar 
to  that  which  he  found  in  Europe.  He  had  seen  no  specimens,  how- 
ever. Supposing  the  disease  to  be  due  to  Sclerotinia,  he  recom- 
mended the  application  of  lime  and  suggested  flooding  the  vines  just 
before  the  spores  are  formed. 

Woronin  9  in  1888  in  treating  of  Sclerotinia  oxycocci  refers  to  the 
cranberry  disease  of  the  eastern  United  States  and  suggests  that  it 
is  caused  by  this  fungus.  This  opinion  was  not  based  on  an  examina- 
tion of  specimens,  however,  but  on  Doctor  Taylor's  accounts  of  the 
disease.  If  the  disease  were  caused  by  Sclerotinia  he  thought  it 
could  be  eradicated  by  collecting  and  burning  all  the  mummied 
berries. 

Xo  species  of  Sclerotinia  has  yet  been  found  on  cranberries  in  the 
East  so  far  as  known,  but,  as  will  be  seen  later,  one  has  been  found 
in  Wisconsin. 

In  1889,  Dr.  Byron  D.  Halsted,10  of  the  New  Jersey  Experiment 
Station,  undertook  a  study  of  the  cranberry  diseases,  arid  as  a  result 
published  a  bulletin  and  several  briefer  reports  on  the  subject. 
Doctor  Halsted  8  recognized  the  parasitic  nature  of  the  disease,  and 
described  and  illustrated,  without  name,  the  twro  stages  of  the  fungus 
which  produces  cranberry  scald.  On  account  of  his  finding  fun- 
gous hyphse  in  the  stems  and  roots  of  plants  bearing  rotten  or  scalded 
berries,  he  concluded  that  the  parasite  infested  the  soil  and  perhaps 
gained  entrance  to  the  plant,  in  part  at  least,  by  way  of  the  roots.  He 
consequently  thought  that  remedies  should  be  directed  chiefly  toward 
the  improvement  of  soil  conditions,11  though  later  he  recommended 
spraying  with  a  solution  of  ammoniacal  copper  carbonate.12  In  his 
later  publication13  he  says:  "It  seems  well  established  that  the 
fungus  infests  all  parts  of  the  plants  and  may  enter  the  berry  by 
means  of  the  filaments  which  grow  from  the  stem  directly  into  the 
green  berry,  or  by  spores  lodging  upon  the  surface,  the  germ  threads 
penetrating  the  fruit."  Doctor  Halsted  10  also  investigated  the  cran- 
berry gall  disease,  which  will  be  referred  to  later. 

Some  work  on  cranberry  diseases  has  also  been  done  at  the  Wis- 
consin Agricultural  Experiment  Station.     This  will  be  referred  to 
later  in  discussing  the  diseases, 
no 


12  CRANBERRY    DISEASES. 

Ill  1901,  at  the  urgent  request  of  the  American  Cranberry  Growers' 
Association  and  in  cooperation  with  the  New  Jersey  Experiment 
Station,  a  study  of  cranberry  diseases  on  behalf  of  the  Bureau  of 
Plant  Industry  was  commenced  by  the  writer.  Both  field  and  labo- 
ratory investigations  have  been  continued  since  as  the  pressure  of 
other  duties  would  permit.  Careful  studies  were  first  made  of  the 
field  conditions,  and  laboratory  and  greenhouse  studies  have  been 
made  of  the  diseases  found  and  the  fungi  producing  them. 

THE   MOST   SERIOUS   DISEASES. 

Cultures  of  the  fungi  found  in  diseased  berries  soon  showed  that, 
instead  of  a  single  disease,  the  term  "  scald  "  as  used  by  cranberry 
growers  includes  at  least  three  distinct  diseases  of  the  fruit — scald, 
rot,  and  anthracnose — caused  by  three  different  fungous  parasites, 
Guignardia  vaccinii  Shear,  Acanthorhynchus  vaccinii  Shear,  and 
Glomerella  rufomaculans  vaccinii  Shear.  Besides  the  diseases  which 
affect  the  more  or  less  mature  fruit  there  is  another,  commonly  called 
u  blast,"  or  sometimes  "  blight,"  by  the  cranberry  growers,  which 
attacks  the  very  young  berries  about  the  time  the  blossoms  fall, 
causing  them  to  turn  black  and  shrivel  up.  There  is  also  a  disease 
which  causes  hypertrophy  of  the  axillary  leaf  buds,  and  thus  ex- 
hausting the  vitality  of  the  plant  prevents  the  production  of  fruit. 
The  most  important  diseases  of  the  cranberry  are  those  mentioned. 
Besides  these  there  are  a  number  of  diseases  of  minor  importance 
which  will  receive  briefer  consideration. 

BLAST. 

As  already  mentioned,  the  blast  attacks  the  flowers  and  very  young 
fruit,  which  shrivels  up  and  becomes  covered  with  the  pycnidia  of 
the  parasite  (PL  II,  figs,  la,  16).  It  frequently  happens  that  as 
much  as  one-half  of  the  crop  on  some  bogs  or  portions  of  bogs  is 
destroyed  in  this  manner.  The  disease  is  caused  by  the  pycnidial 
form  of  Guignardia  vaccinii  Shear.24  The  blasting  of  young  fruit 
had  been  observed  for  many  years  by  cranberry  growers,  but  appar- 
ently the  fungous  nature  of  the  disease  was  not  known.  There 
is,  of  course,  some  blast,  or  blight,  of  blossoms  and  of  very  young 
fruit  due  to  other  causes,  as  imperfect  fertilization  or  injury  by 
storms,  frost,  or  insects,  but  by  far  the  greater  part  of  the  blasted 
fruit  on  New  Jersey  cranberry  bogs  is  due  to  the  above-mentioned 
fungus. 

Whitson,  Haskins,  and  Malde15  mention  a  cranberry  "blight" 

which  occurs  in  Wisconsin,  killing  the  blossoms  and  very  small  fruit. 

This  trouble,  according  to  the  writers  mentioned,  has  been  attributed 

by  growers  to  hot  weather.     The  results  of  their  experiments  were 

no 


SCALD.  13 

contrary  to  this  theory.  They  concluded  from  their  trials  with 
several  fertilizers  that  the  blight  depended  largely  upon  the  vitality 
of  the  vines.  Plats  treated  with  phosphates  showed  least  blight. 
In  conclusion  they  say :  "  The  agent  of  destruction  of  these  blossoms 
is  probably  a  bacterial  or  fungus  growth  which  takes  place  only 
under  a  devitalized  or  weakened  condition.''  Having  had  no  oppor- 
tunity to  make  a  study  of  the  blight,  or  blast,  in  Wisconsin,  we  are 
unable  to  say  how  much  of  it  may  be  due  to  Guignardia  vaccinii, 
which  produces  the  blast,  or  blight,  in  the  East.  From  the  fact  that 
this  fungus  occurs  in  Wisconsin  and  destroys  more  or  less  of  the 
fruit,  it  is  highly  probable  that  some  of  the  blight,  or  blast,  is  also 
caused  by  it.  The  "  blossom  blight "  is  also  mentioned  by  Whitson, 
Sandsten,  Haskins,  and  Ramsey.10  They  state  that  a  treatment  for 
blight  of  three  applications  of  Bordeaux  mixture  produced  an 
increase  of  30  per  cent  in  the  crop  of  fruit  over  that  on  adjacent 
vines  not  treated.  This  would  seem  to  indicate  that  the  disease  is  of 
a  fungous  nature. 

SCALD. 

The  term  u  scald  "  is  one  which  has  been  in  general  use  among 
the  New  Jersey  cranberry  growers  for  a  long  time.  It  originated 
as  a  result  of  a  view  previously  held  by  many  growers  that  the 
softening  of  the  diseased  fruit  was  due  to  an  actual  scalding  of  the 
berry,  caused  by  the  hot  sunshine  when  the  berries  were  wet. 

A  condition  somewhat  resembling  the  effect  of  the  fungus  does 
sometimes  occur  when  berries  have  been  overflowed  and  covered 
with  water  for  half  a  day  or  more  during  hot  weather,  but  injury 
of  this  kind  is  infrequent  and  unimportant. 

The  first  indication  of  the  attack  of  the  scald  fungus  upon  the 
cranberry  is  the  appearance  of  a  minute,  light-colored,  watery  spot 
upon  its  surface.  This,  under  favorable  conditions,  rapidly  spreads, 
usually  in  a  concentric  manner,  until  finally  the  whole  berry  becomes 
soft  (PI.  I).  Frequently  the  diseased  area  is  marked  by  con- 
centric dark-colored  rings.  This,  however,  is  not  always  the  case, 
and  is  not  especially  characteristic  of  this  disease,  as  it  sometimes 
occurs  in  the  case  of  the  cranberry  rot.  In  very  rare  instances  only 
a  small,  light-colored  sunken  spot  is  produced  upon  the  berry,  the 
fungus  by  some  unknown  cause  having  been  retarded  or  entirely  pre- 
vented from  further  development.  In  such  cases  we  occasionally  find 
the  pycnidia  of  the  scald  fungus  present,  as  illustrated  by  Doctor  Hal- 
sted  10  in  his  work  on  cranberry  scald.  Ordinarily,  however,  there 
is  no  indication  on  the  surface  of  the  fruit  of  the  presence  of  a 
fungus,  except  for  occasional  dark  blotches  or  brownish  zones,  as 
mentioned  above.  Berries  which  are  attacked  before  they  are  half 
grown  usually  shrivel  up  and  become  blackened  and  covered  with 
no 


14  CRANBERRY   DISEASES. 

the  pycnidia  of  the  scald  fungus  (PL  II,  fig.  1,  &,  and  PL  VI).  This 
form  of  the  disease  is  called  blast,  as  already  described. 

The  disease  also  affects  the  leaves,  occasionally  causing  an  irregular 
reddish  brown  spot,  covering  a  portion  of  the  leaf,  and  bearing 
pycnidia  or  perithecia  of  the  fungus.  These  spots  are  of  very  infre- 
quent occurrence.  Where  the  disease  has  been  severe  for  a  number 
of  years  the  plants  are  completely  killed,  and  the  dead,  brown  leaves 
still  hanging  to  the  vines  are  usually  covered  on  the  under  surface 
with  the  minute  fruiting  bodies  of  the  parasite  (PL  II,  fig.  1). 

Cuttings  the  first  year  or  two  after  planting  and  before  fruiting 
are  sometimes  seriously  attacked  by  Guignardia  vaccinii,  which 
causes  the  leaves  to  turn  yellow  and  fall  and  finally  kills  the  plant. 
Some  of  the  other  cranberry  fungi  are  also  associated  with  this 
injury,  but  the  greater  part  of  the  damage  is  apparently  due  to  the 
scald  fungus. 

THE   FUNGUS    (GUIGNARDIA   VACCINII,    SHEAR)    CAUSING   BLAST 

AND  SCALD. 

Scalded  or  rotten  berries  so  rarely  show  any  fruiting  forms  of 
fungi  that  it  is  necessary  to  determine  their  presence  and  identity 
by  careful  microscopical  examination  and  cultures.  A  microscopic 
study  of  the  softened  tissues  of  scalded  berries  at  once  reveals  the 
presence  of  an  abundance  of  fungous  hyphse.  These  hyphse  when 
transferred  to  culture  media  grow  readily  and  frequently  produce 
the  fruiting  forms  of  the  fungus.  This  fungus,  Guignardia  vaccinii 
Shear,24  which  has  been  found  upon  blasted  berries,  upon  the  leaves 
of  scalded  vines,  and  isolated  in  numerous  cases  in  pure  cultures 
from  scalded  fruit,  has  been  grown  in  the  laboratory  for  several 
years. 

Whitson,  Sandsteri,  Haskins,  and  Kamsey16  state  that  the  cran- 
berry scald  in  Wisconsin  is  caused  by  an  unnamed  species  of  Rosel- 
linia.  We  have  never  found  any  fungus  of  this  genus  associated 
with  cranberry  scald  or  any  other  disease  of  the  cranberry  in  Wis- 
consin or  elsewhere.  The  only  cranberry  fungus  which  at  all  resem- 
bles Rosellinia  is  Anthostomella  destruens  Shear,  which  has  been 
found  only  once  in  our  investigations,  and  then  in  New  Jersey.  The 
true  scald  fungus  (Guignardia  vaccinii}  has,  however,  been  found  in 
Wisconsin  berries.  There  are  two  stages  thus  far  known  in  the 
course  of  its  development,  a  pycnidial  and  an  ascogenous  stage. 

Pycnidial  form. — The  pycnidia  are  minute,  black,  membranous, 
globose  receptacles,  100-120^  in  diameter,  provided  with  a  minute 
apical,  sometimes  slightly  prominent  ostiole,  or  mouth.  When  oc- 
curring on  the  leaves  they  are  situated  beneath  the  epidermis,  usually 
on  the  under  side,  and  are  slightly  erumpent,  with  the  minute  ostiole 
no 


THE    FUNGUS    CAUSING    BLAST    AND    SCALD.  15 

exposed.  In  most  cases  they  are  thickly  and  evenly  distributed  over 
the  sui'face  of  the  leaf,  except  for  the  infrequent  occasions  when  only 
a  portion  of  the  leaf  has  been  killed  by  the  fungus  (PL  II,  figs.  1  and 
2).  Mature  pycnidia  contain  great  numbers  of  pycnospores,  bearing 
at  their  apexes  a  rather  inconspicuous  appendage  consisting  of 
granular  matter,  which  appears  to  be  embedded  in  a  somewhat  gelat- 
inous substance.  They  are  borne  on  short,  simple  sporophores  10-15  ^ 
long.  These  pycnospores  are  hyaline,  obovoid,  with  the  apex  fre- 
quently truncate,  and  measure  from  10.5  to  13.5  by  5  to  6  ^.  The 
appendage  is  usually  about  the  length  of  the  spore,  or  somewhat  less, 
and  curved  (PL  II,  fig.  3,  «,  6,  c).  At  maturity  these  pycnospores 
are  expelled  from  the  pycnidium  in  a  small  gelatinous  tendril  or 
threadlike  mass,  being  held  together  by  the  gelatinous  substance  of 
the  spore  appendages  as  Avell  as  the  free  gelatinous  matter  which 
appears  to  be  produced  within  the  pycnidium  and  forms  a  thin  layer 
about  the  pycnospore. 

Ascogenovs  form. — The  ascogenous  perithecia  are  much  less  fre- 
quently found  than  the  pycnidia.  The  perithecia  resemble  the  pyc- 
nidia very  closely  in  form,  size,  and  other  characteristics  (PL  II, 
fig.  10).  In  fact  it  is  almost  or  quite  impossible  to  determine,  in  the 
absence  of  asci  or  pycnospores,  to  which  form  a  particular  fruiting 
body  may  belong.  The  perithecia  seem  to  have  a  denser,  somewhat 
more  opaque  wrall  than  the  pycnidia,  and  they  contain  oblong,  or 
somewhat  clavate,  short-stipitate,  or  sessile  asci,  the  spore-bearing 
portion  varying  from  52  to  60  by  9  to  12  ^  the  total  length  being  GO 
to  80  fji  (PL  II,  fig.  11).  The  asci  contain  eight  hyaline,  or,  when 
old,  slightly  yellowish  brown,  short  elliptical  or  subrhomboid  asco- 
spores,  having  the  contents  rather  coarsely  granular  (PL  II,  fig.  12). 
They  vary  in  size  from  13  to  16.5  by  6  to  T/x.  No  paraphyses  have 
been  found.  The  characters  of  the  ascogenous  form  of  this  fungus 
seem  to  agree  most  nearly  with  those  of  the  genus  Guignardia  and 
correspond  very  closely  to  the  black-rot  fungus  of  the  grape  (Guig- 
nardia ImJwellii  (Ell.)  V.  &  R.).  The  pycnidial  stage  of  Guignardia 
bidwellii,  as  described  and  illustrated  by  Viala  18  and  others,  differs 
from  the  pycnidial  stage  of  the  cranberry  scald  fungus  in  scarcely 
any  particular  except  in  the  absence  of  the  spore  appendage.  A 
recent  careful  study  of  fresh  pycnidia  of  (Guignardia  bidweUii  shows 
that  its  pycnospores  also  bear  a  similar  appendage.  It  is,  however, 
shorter  and  less  easily  distinguished  than  that  of  Guignardia  raccinii, 
and  soon  disappears  in  mounted  specimens.  The  appendage  in  the 
case  of  the  cranberry  fungus  is  very  constant  and  characteristic. 

The  cranberry  scald  fungus  is  rather  generally  distributed  through- 
out the  cranberry-growing  sections  of  this  country.  Pycnidia  have 
been  found  on  either  leaves,  flowers,  or  fruit  in  West  Virginia,  New 
no 


16  CRANBERRY   DISEASES. 

Jersey,  Massachusetts,  Nova  Scotia,  Wisconsin,  and  New  York,  and 
perithecia  in  New  Jersey  and  New  York. 

CULTURES   OF   GUIGNARDIA    VACCINII. 

Over  200  cultures  from  hyphae,  pycnospores,  and  ascospores  have 
been  made  upon  artificial  media  of  various  kinds.  The  first  cultures 
of  the  fungus  were  niade  from  hyphae  taken  from  the  interior  of 
scalded  berries.  The  berries  were  first  thoroughly  washed  and 
soaked  in  a  1  to  1,000  solution  of  corrosive  sublimate  (HgCL).  and 
a  portion  of  the  pulp  containing  the  fungous  hyphae  was  transferred 
with  sterile  needles  to  the  culture  medium. 

The  following  culture  media  have  been  used:  Cylinders  of  pota- 
toes and  of  beets ;  steam-sterilized  and  dry-sterilized  cranberry  leaves 
and  cranberry  fruit;  cranberry  agar  and  cranberry  gelatin,  pre- 
pared by  adding  various  proportions  of  cranberry  juice  to  agar  and 
gelatin;  beef  agar  and  sugar-beet  agar;  corn  meal  saturated  with 
cranberry  agar;  corn  meal  saturated  with  cranberry  gelatin;  malta 
vita  saturated  with  cranberry  agar,  and  corn  meal  saturated  with 
distilled  water.  It  appears  to  grow  equally  well  upon  acid  and 
neutral  media. 

We  have  had  the  greatest  and  most  uniform  success  in  the  use  of 
corn  meal  and  water  sterilized  in  an  autoclave  for  about  fifteen  min- 
utes. The  fungus  also  grows  readily  on  corn  meal  saturated  with 
cranberry  agar,  corn  meal  saturated  with  cranberry  gelatin,  and  on 
potatoes.  It  grows  more  slowly  and  less  luxuriantly  on  most  of  the 
other  media  tried. 

Pycnidial  form. — Cultures  producing  the  pycnidial  form  have  been 
made  from  the  pulp  and  skin  of  diseased  fruits  in  thirty-eight  differ- 
ent cases  and  from  leaves  in  two  instances.  This  form  has  also  been 
grown  from  pycnospores.  The  mycelium  in  all  cases  is  at  first  thin, 
floccose,  and  white.  In  a  few  days  it  becomes  denser  and  takes  on  a 
bluish  gray  color.  As  the  culture  gets  older  the  hyphae  spread  con- 
centrically and  the  mycelium  loses  its  bluish  tint  and  becomes  grayish 
brown.  Pycnidia  begin  to  appear  in  four  to  eight  days,  and  mature 
pycnospores  can  usually  be  found  in -twelve  to  eighteen  days.  The 
pycnidia  form  a  more  or  less  continuous  layer  on  the  surface  of  the 
somewhat  felty  subiculum  formed  by  the  mycelium.  They  are  fre- 
quently inconspicuous  on  account  of  the  velvety  surface  growth  of 
hyphae,  with  which  the  mycelial  layer  is  covered.  In  the  majority  of 
cultures  made  from  hyphae  taken  from  diseased  berries  only  pycnidia 
are  produced,  and  in  many  instances  the  culture  has  all  the  character- 
istics of  growth  and  appearance  of  Guignardia  vaccinii,  but  is  either 
entirely  sterile  or  produces  sclerotia-like  bodies  resembling  pycnidia 
externally  but  containing  no  spores, 
no 


CULTURES    OF    GUIGNARDIA    VACCINII.  17 

Ascogenous  form. — Cultures  producing  both  pycnidia  and  asci  have 
been  obtained  in  five  cases  by  transplanting  the  fungous  hyphae  from 
diseased  berries,  and  in  three  cases  from  affected  leaves,  to  culture 
media. 

The  first  successful  culture  was  made  from  decaying  fruit  obtained 
in  the  Washington  market.  The  source  of  the  fruit  is  unknown,  but 
it  was  probably  from  New  Jersey.  The  culture  was  made  on  March 
31,  190'2.  The  berries  used  were  softened;  the  skin  was  light  colored 
and  watery  and  showed  small  dark-colored  blotches  of  fungous 
hyphap  on  the  inner  surface.  Two  cultures  were  made  from  one  of 
these  berries  by  transferring  portions  of  the  pulp  containing  the 
hypha?  to  flasks  of  cranberry  agar  and  corn  meal.  The  cultures  were 
kept  in  the  laboratory  at  the  ordinary  temperature,  which  varied 
from  16  to  25°  C.  The  course  of  development  and  appearance  of 
the  fungus  were  the  same  as  in  the  cultures  producing  pycnospores 
only,  as  previously  described.  Mature  pycnidia  were  produced  in 
about  twelve  to  fifteen  days,  and  at  the  end  of  twenty-two  days  a  great 
abundance  of  ascogenous  perithecia  was  found.  There  is  nothing 
in  the  macroscopic  appearance  of  a  culture  bearing  ascogenous 
perithecia  to  distinguish  it  from  one  bearing  only  pycnidia.  The 
ascogenous  perithecia  are  practically  identical  in  appearance  with  the 
pycnidia.  In  mature  and  old  cultures  the  color  of  the  mycelium 
becomes  dark  brown,  or  almost  black,  and  the  pycnidia  or  perithecia 
become  more  exposed  on  the  surface  of  the  subiculum  or  crustlike 
stroma. 

The  second  successful  culture  of  the  ascogenous  form  was  made 
January  20,  1903,  by  transferring  a  portion  of  the  skin  of  a  diseased 
berry  showing  darkened  spots  to  a  flask  of  water-saturated,  autoclaved 
corn  meal.  The  course  of  development  was  the  same  as  in  the  culture 
just  described.  Many  bodies  resembling  pycnidia  were  produced  at 
first,  but  all  examined  were  apparently  sterile.  Later,  in  addition 
to  these  sterile  bodies,  ascogenous  perithecia  of  Guignardia  were 
found. 

The  third  successful  culture,  of  ascogenous  perithecia  was  made 
December  23,  1903,  from  diseased  New  Jersey  berries,  which  had 
been  kept  in  ordinary  storage  in  an  unheated  building  in  the  Depart- 
ment. These  berries  showed  the  ordinary  appearance  of  scalded 
fruit,  and  the  cultures  were  made  by  transferring  sections  of  diseased, 
berries  which  had  been  washed  and  soaked  in  a  solution  of  corrosive 
sublimate  to  flasks  of  sterilized  corn  meal.  An  abundance  of  fertile 
pycnidia  was  produced,  and  at  the  end  of  nineteen  days  perithecia 
containing  mature  asci  were  found. 

The  fourth  successful  culture  was  also  made  at  the  same  time  as 
the  last  mentioned,  and  from  fruit  from  the  same  source,  treated  in 
the  same  manner. 

3525— No.  110—07  M 3 


18  CRANBERRY    DISEASES. 

The  fifth  successful  culture  from  diseased  berries  was  made  May 
10,  1904.  The  berries  Avere  received  from  Cranmoor,  Wis.  They 
were  softened  and  shriveled  and  showed  definite  black  spots  011  the 
surface.  After  washing  and  soaking  for  three-fourths  of  an  hour 
in  corrosive-sublimate  solution,  sections  of  the  diseased  portion,  in- 
cluding the  skin,  were  transferred  to  large  tubes  of  sterilized  corn 
meal.  About  one  month  later  ascogenous  perithecia  of  Guignardia 
were  found  in  this  culture.  Several  other  cultures  made  at  the  same 
time  upon  the  same  culture  medium  and  from  fruit  having  the  same 
appearance  produced  only  pycnidia.  Transfers  made  from  cultures 
producing  asci  to  sterile  potato  cylinders  have  produced  the  ascoge- 
nous form  as  quickly  and  'abundantly  as  when  grown  on  corn  meal. 

Besides  the  successful  cultures  just  described,  which  have  been  made 
from  diseased  berries,  we  have,  in  three  instances,  obtained  from 
cranberry  leaves  pure  cultures  bearing  both  pycnidia  and  asci. 

On  March  23,  1905,  cultures  were  made  by  placing  in  flasks  of 
sterile  corn  meal  leaves  which  had  been  first  soaked  for  about  onp 
hour  in  a  1  to  500  solution  of  corrosive  sublimate  and  then  cut  in 
two  pieces.  These  leaves  were  taken  from  vines  which  had  borne 
very  badly  scalded  fruit  during  the  previous  season.  The  vines  were 
collected  on  November  29,  1904,  and  kept  in  an  ice  box  from  that 
time  until  the  cultures  were  made.  The  leaves  were  of  1903  growth 
and  were  to  all  external  appearances  healthy  and  free  from  fungi. 
Leaves  taken  from  this  collection  in  March,  1906,  still  produced  plenty 
of  good  pycnidia  and  ascogenous  perithecia.  The  course  of  develop- 
ment of  the  fungus  in  these  cultures  was  identical  with  that  described 
in  the  other  cases.  Pycnidia  were  produced  in  abundance  in  about 
fifteen  days,  and  at  the  end  of  twenty-nine  days  ascogenous  perithecia 
were  found  in  three  of  the  cultures. 

From  these  original  cultures  many  others  have  been  made  by  trans- 
fer. Four  generations  have  been  grown  in  this  way,  producing  both 
pycnospores  and  ascospores  in  each.  After  this  the  fungus  appeared 
to  have  lost  its  vitality  and  did  not  grow  well.  In  other  cases  it 
developed  both  spore  forms  for  one  or  two  generations  only. 

The  fresh  pycnospores  of  this  fungus  germinate  and  grow  readily 
in  water,  in  a  dilute  solution  of  sugar  and  water,  and  in  ordinary 
culture  media.  Spores  placed  in  a  drop  culture  of  sugar  water  in  the 
laboratory  began  to  show  signs  of  germination  at  the  end  of  two  days. 
The  germ  tube  usually  arises  from  the  side  of  the  pycnospore,  first 
forming  a  slight  enlargement,  which  rapidly  elongates  into  a  germ 
tube  and  soon  begins  to  branch  (PL  II,  figs.  4  to  9).  At  the  end  of 
four  days  many  of  the  germ  tubes  have  attained  considerable  length. 
The  tube  occasionally  arises  from  the  basal  end  of  the  spore  (PL  II, 
fig.  6),  but  we  have  never  seen  it  arise  from  the  apical  end,  where  the 
no 


THE    PRODUCTION    OF    THE    ASCOGENOUS    FORM.  19 

appendage  is  borne.  The  mycelium  now  grows  more  rapidly  and  soon 
assumes  the  color  and  other  characteristics  mentioned  in  the  descrip- 
tion of  the  macroscopic  appearance  of  cultures  of  the  fungus. 

The  appendage  of  the  pycnospore,  as  seen  upon  immature  spores, 
consists  of  a  hazy,  hyaline,  finely  granular,  gelatinous  mass,  equaling 
the  spore  in  diameter  (PI.  II,  fig.  3).  A  little  later  it  becomes  some- 
what elongated,  curved  backward,  and  more  or  less  appressed  on  the 
side  of  the  spore.  As  the  spore  matures  the  appendage  becomes  still 
narrower  and  free  from  the  side  of  the  spore,  but  even  at  maturity  it 
is  usually  somewhat  curved.  In  old  cultures  which  have  passed 
maturity  and  in  which  all  the  spores  have  been  set  free,  the  append- 
age is  frequently  wanting  and  seems  to  have  been  dissolved  or 
disintegrated. 

No  signs  of  a  conidial  form  of  the  fungus  have  been  found  in  any 
of  the  numerous  cultures  made,  either  from  the  mycelium  or  spores. 
No  chlamydospores  have  been  found  in  cultures,  but  what  appear  to 
be  such  are  found  in  old  berries  destroyed  by  the  fungus.  Sterile 
pycnidia  or  perithecia  are  frequently  found,  especially  in  poorly 
developed  cultures.  These  are  sometimes  solid  and  sclerotoid,  with 
the  interior  cells  lighter  colored,  and  are  about  the  same  size  as  the 
pycnidia  and  perithecia. 

CONDITIONS    OR    FACTORS    DETERMINING    THE    PRODUCTION    OF    THE 
ASCOGENOUS    FORM. 

The  reasons  for  the  rare  occurrence  of  ascus-bearing  forms  in  cul- 
tures of  what  are  undoubtedly  ascomycetous  fungi  have  always  been 
obscure,  and  it  has  usually  been  found  impossible  to  produce  the 
ascogenous  fructifications  with  much  frequency  or  certainty. 

The  w^ork  of  J£lebs19  and  others  upon  the  effect  of  various  nutrient 
and  other  substances  upon  the  production  of  sexual  fructification, 
especially  in  the  alga?,  has  suggested  the  possibility  of  such  factors 
having  a  determining  influence  on  the  production  of  the  ascogenous 
stage  in  this  fungus.  While  our  experiments  in  this  direction  have 
been  comparatively  few,  there  has  been  no  indication  that  the  compo- 
sition of  the  culture  medium  is  of  particular  importance  in  this 
respect.  When  once  an  ascus-producing  race,  strain,  or  generation 
of  the  fungus  was  obtained  it  grew  almost  equally  well  upon  different 
culture  media,  such  as  steamed  corn  meal,  cranberry  gelatin  and  corn 
meal,  cranberry  agar  and  corn  meal,  and  potatoes. 

The  effect  of  variations  in  temperature  has  also  been  tried  upon 
a  series  of  pycnospore-producing  cultures  made  from  the  same 
original  pure  culture.  Cultures  in  flasks  on  corn  meal  were  kept 
in  the  laboratory,  where  the  temperature  varied  from  20°  to  26°  C. 
Others  were  kept  in  a  thermostat  at-  a  temperature  of  30°  C.  Others 
110 


20  CKANBERRY    DISEASES. 

have  been  kept  in  a  refrigerator  at  a  temperature  of  about  3°  C. 
The  cultures  kept  in  the  laboratory  made  the  most  rapid  and  vigorous 
growth  of  mycelium,  those  in  the  thermostat  and  refrigerator  grow- 
ing about  one-half  as  fast.  All  these  cultures  finally  produced 
pycnidia,  but  no  signs  of  asci  were  ever  found. 

Experiments  have  also  been  tried  to  determine  the  effect  of  differ- 
ent quantities  of  moisture.  The  fungus  was  found  to  grow  more 
rapidly  on  a  rather  wet  medium,  but  there  is  no  indication  that  this 
influences  the  production  of  the  ascogenous  stage  of  the  fungus. 

Other  experiments  were  tried  to  determine  the  effect  upon  the 
growth  and  development  of  the  fungus  of  varying  the  amount  of 
available  air  and  the  evaporation  by  plugging  the  culture  flasks  more 
or  less  tightly.  Little  or  no  difference  was  noticeable  in  the  growth 
in  these  flasks,  and  only  pycnidia  were  produced. 

The  work  of  Blakeslee 20  on  Mucor  and  the  factors  controlling  the 
production  of  zygospores  in  that  and  related  genera  has  suggested 
the  possibility  that  the  sexual  or  ascogenous  fructification  might 
arise  from  the  union  of  different  races  or  individuals.  The  few 
experiments  we  have  made  along  this  line,  however,  have  been 
unsuccessful. 

It  has  been  thought  by  Brefeld  21  that  ascus  formation  may  depend 
upon  the  time  of  the  year,  or  possibly  the  period  of  development  of 
the  fungus  in  its  host.  Our  investigations,  however,  are  not  conclu- 
sive in  regard  to  these  points,  so  far  as  they  concern  Guignardia 
vaccinii.  Cultures  have  been  made  from  fruit  and  leaves  taken 
almost  every  month  during  the  year,  and  it  will  be  noted  that  cul- 
tures which  produced  the  ascogenous  stage  of  the  fungus  were  made 
in  January,  March,  May,  and  December.  Many  other  cultures,  how- 
ever, made  during  these  same  periods  and  from  leaves  and  fruit  in 
which  the  fungus  had  presumably  passed  through  approximately 
the  same  period  of  development  were  either  sterile  or  produced 
pycnidia  onlv.  While  we  have  no  cultures  made  from  material  taken 
during  the  summer  which  have  produced  ascospores,  this  may  be 
due  to  the  fact  that  comparatively  few  cultures  have  been  made  from 
leaves  or  fruit  during  that  season. 

In  regard  to  the  bearing  of  the  duration  of  development  of  the 
fungus  upon  the  production  of  asci,  we  have  no  means  at  hand  of 
determining,  except  by  mere  conjecture,  the  age  of  the  fungus  which 
may  be  present  at  any  particular  time  in  the  tissues  of  cranberry 
leaves  or  fruit,  not  knowing  positively  when  the  infection  took  place 
and  the  germ  of  the  fungus  entered  the  plant.  All  the  evidence  at 
hand,  however,  points  toward  June  and  July  as  the  time. 

As  a  result  of  our  work,  we  are  led  to  the  belief  that  there  is  some 
inherent  potentiality  in  the  mycelium  of  the  fungus  in  certain  strains, 
no 


DORMANT  CONDITION  OF  THE  FUNGUS.  21 

races,  or  generations  which  causes  it  to  produce  the  ascogenous  stage 
whenever  conditions  for  its  growth  are  favorable,  i.  e.,  on  favorable 
culture  media  without  special  reference  to  their  exact  composition 
or  environment  or  on  the  leaves  of  its  natural  host.  Whether  this 
potentiality  depends  on  some  preceding  union  of  nuclei  from  dif- 
ferent or  the  same  individuals,  or  some  equivalent  stimulus,  we  are, 
of  course,  unable  to  say.  It  appears  possible,  however,  that  there 
may  be  such  a  factor  concerned. 

DORMANT   CONDITION    OF   THE    FUNGUS. 

Leaves  and  berries  which,  so  far  as  can  be  discovered  by  external 
examination,  are  perfectly  sound  are  very  frequently  found  to  con- 
tain the  fungus.  Leaves  perfectly  normal  in  appearance,  taken  from 
vines  growing  in  diseased  areas,  have  been  thoroughly  washed  and 
soaked  from  fifteen  minutes  to  two  hours  in  a  solution  of  corrosive 
sublimate,  1  part  to  500  parts  of  water,  in  order  to  destroy  any 
fungous  spores  which  might  possibly  be  present  upon  their  surfaces. 
These  leaves  were  then  placed  in  sterile,  moist  chambers.  After  a 
period  of  eight  to  twelve  days  an  abundance  of  the  pycnidia  of 
Guignardia  raccinii  was  found  to  have  developed  upon  the  leaves,  and 
in  some  instances  these  were  followed  by  the  ascogenous  form  of  the 
fungus.  Berries  apparently  perfectly  sound  and  healthy  have  also 
been  treated  in  the  same  manner,  and  in  many  cases  the  characteristic 
decay  of  the  fruit  has  followed.  Cultures  made  from  the  pulp  of 
these  berries  have  produced  the  fruiting  forms  of  the  Guignardia. 

So  many  experiments  of  this  kind  have  been  tried  that  we  feel 
convinced  that  the  fungus  must  be  present  within  the  tissues  of  the 
leaves  and  berries  referred  to  in  a  dormant  or  more  or  less  inactive 
condition.  It  does  not  seem  possible  that  any  spores  could  resist  the 
action  of  the  corrosive  sublimate  solution  used.  Tests  which  have 
been  made  show  that  the  spores  of  Guignardia  vaccinii  are  killed 
by  being  immersed  in  a  1  to  1,000  solution  of  corrosive  sublimate  for 
five  minutes.  A  great  number  of  microtome  sections  of  leaves  and 
fruit  supposed  to  contain  the  dormant  form  of  the  fungus  have  been 
studied.  It  has  been  found  very  difficult  to  demonstrate  the  presence 
of  the  fungus  and  to  determine  its  form,  chiefly,  perhaps,  on  account 
of  unsatisfactory  results  in  differential  staining. 

In  case  of  the  berries,  carefully  stained  sections  have  shown  what 
appear  to  be  cells  of  fungous  hypha?  just  beneath  the  epidermis.  In 
both  leaves  and  fruit  the  fungus  seems  to  be  able  to  exist  in  the 
tissues  in  a  more  or  less  inactive  or  dormant  condition  while  await- 
ing an  opportunity  for  further  development;  such  opportunity  is 
apparently  afforded  by  any  conditions  which  weaken  the  cranberry 
plant  and  also  by  those  which  are  favorable  to  the  growth  of  the 
no 


22  CRANBERRY   DISEASES. 

fungus,  such  as  sufficient  heat  and  moisture.  If  a  similar  condition  of 
affairs  should  prove  to  obtain  rather  generally  among  similar  para- 
sitic fungi,  as  seems  to  be  possible  from  observations  and  experiments 
made  with  other  cranberry  diseases  and  several  anthracnoses  on 
different  hosts,  it  will  have  an  important  bearing  upon  the  results 
and  conclusions  derived  from  ordinary  infection  experiments  in 
which  plants  have  been  used  which  were  not  grown  from  uninfected 
seed  under  conditions  which  would  preclude  possible  infection  at 
any  time  previous  to  their  use.  It  would  also  have  an  important 
bearing  upon  the  value  of  inferences  regarding  the  time  of  infection 
based  upon  the  time  of  the  outbreak  of  the  disease. 

It  has  been  supposed  that  in  the  case  of  diseases  such  as  the  black- 
rot  of  the  grape  the  time  of  its  external  destructive  appearance  fol- 
lowed within  a  short  period  after  the  germs  of  the  disease  had  entered 
the  tissues  of  the  plant.  In  other  words,  it  has  been  taken  for 
granted  that  as  soon  as  a  germ  tube  gains  entrance  to  the  tissues  of 
its  host  it  proceeds  to  develop  under  normal  conditions  and  soon  pro- 
duces its  characteristic  injuries.  On  the  contrary,  however,  it  seems 
much  more  probable  that  there  is  no  regular  period  of  incubation, 
but  that  the  development  of  the  parasite  depends  largely  upon  the 
conditions  surrounding  it  and  its  host.  If  the  host  plant  becomes 
weakened  in  any  way  or  if  the  conditions  of  heat  and  moisture  are 
especially  favorable  for  the  fungus  its  development  may  be  rapid  and 
continuous,  but  if  these  conditions  do  not  obtain  the  fungus  may 
remain  in  an  inactive  or  dormant  condition,  or  its  development  may 
be  very  slow  or  intermittent  and  in  some  cases  perhaps  entirely  sup- 
pressed. Many  illustrations  of  this  condition  can  apparently  be 
found  among  foliicolous  pyrenomycetes  which  develop  their  fruits 
so  abundantly  during  the  winter  on  old  fallen  leaves.  There  is  no 
evidence,  so  far  as  we  know,  that  infection  of  these  leaves  takes  place 
during  the  winter.  The  scanty  observations  which  have  been  made 
indicate  rather  that  the  mycelium  is  present  in  the  leaves  when  they 
fall,  though  there  is  no  outward  indication  of  its  presence. 

TIME    AND    MANNER    OF    INFECTION. 

We  have  been  unable  thus  far  to  discover  exactly  when  and  in  what 
manner  infection  of  the  leaves  and  fruits  takes  place.  The  pycnidial 
form  of  the  fungus  may  be  found  within  from  ten  to  fifteen  days 
after  the  water  with  which  the  vines  are  usually  flooded  during  the 
wrinter  has  been  removed.  This  appears  to  be  about  the  normal 
period  required  for  the  development  of  the  pycnidia  when  the  growth 
of  the  fungus  is  regular  and  continuous,  as  shown  by  its  growth  and 
development  in  pure  cultures.  The  pycnidia  appear  first  upon  old 
leaves  of  vines  which  have  apparently  been  weakened  or  killed  by  the 
no 


TIME   AND    MANNER   OF    INFECTION.  23 

disease.  A  great  number  of  pycnospores  are  also  produced  about  the 
1st  of  July  upon  the  very  small  blasted  berries.  These  are  probably 
the  chief  source  of  the  infections  which  follow.  The  pycnospores  may 
also  be  found  more  or  less  abundantly  during  the  whole  season  upon 
old  dead  and  dying  leaves,  especially  of  those  vines  which  have  been 
cut  and  broken. 

The  ascogenous  form  is  apparently  not  of  very  frequent  occur- 
rence. It  has  been  collected  occasionally  on  old  leaves  from  June  to 
November,  but,  judging  from  the  small  quantity  found,  it  does  not 
seem  probable  that  it  is  a  very  important  factor  in  the  general  dis- 
tribution and  spread  of  the  disease.  Ascospores  in  most  pyreno- 
mycetous  fungi  appear  to  be  produced  normally  in  late  winter  and 
spring.  The  abnormal  conditions  under  which  the  cultivated  cran- 
berry is  grown — the  plants  being  generally  flooded  with  water  from 
November  until  May — prevent  the  production  of  the  fruiting  forms 
of  the  fungus  during  that  period.  We  have  found  by  laboratory  ex- 
periments that  the  fungus  does  not  develop  upon  leaves  when  they  are 
kept  immersed  in  water.  Twigs  with  leaves  from  vines  bearing  very 
badly  scalded  fruit  have  been  kept  in  water  in  the  laboratory  for 
months  without  any  external  indication  of  the  development  of  the 
fungus,  wrhile  leaves  from  the  same  plants  kept  in  moist  chambers 
developed  Guignardia  in  abundance.  In  the  early  stages  of  our  inves- 
tigation various  inoculation  experiments  were  tried,  both  in  the  field 
and  in  the  greenhouse,  using  plants  which  were  presumably  free 
from  disease,  judging  from  the  external  appearance  of  the  vines  and 
berries.  The  results  of  these  experiments  have,  however,  since  been 
shown  to  be  valueless  on  account  of  the  quite  general  occurrence  of 
the  fungus  in  leaves  and  fruit  which  appeared  normal  and  healthy, 
as  already  pointed  out.  In  order,  therefore,  to  make  conclusive  infec- 
tion experiments  it  is  necessary  to  grow  plants  from  seed  in  sterile 
soil  under  conditions  which  will  prevent  possible  infection  from  any 
'source  except  artificial  inoculation.  Thus  far  we  have  been  unable 
to  do  this,  owing  to  the  fact  that  great  difficulty  has  been  experienced 
in  germinating  seeds  and  growing  satisfactory  plants  in  the  green- 
house. From  field  observations  made  in  connection  with  our  spray- 
ing experiments  it  seems  very  probable  that  infection  of  the  young 
leaves  takes  place  very  early  in  the  season,  soon  after  the  water  is 
removed  from  the  bog  and  as  soon  as  the  first  generation  of  pycno- 
spores is  produced  upon  the  old  dead  and  fallen  leaves.  There  are 
also  observations  and  facts  which  seem  to  indicate  that  infection  of 
the  berries  generally  takes  place  when  they  are  rather  young.  This 
is  self-evident  of  course  in  the  case  of  the  blasted  fruit,  which  is 
destroyed  when  it  is  very  small.  Attempts  to  infect  mature  or  nearly 
mature  fruit  in  the  laboratory  have  in  all  cases  been  unsuccessful, 
no 


24  CRANBERRY    DISEASES. 

Fresh  pycnospores  have  been  placed  in  drops  of  water  upon  fruit 
kept  in  sterile  moist  chambers,  but  without  any  noticeable  result. 
The  spores  germinate,  but  are  apparently  unable  to  penetrate  the 
epidermis  of  the  fruit.  That  infection  of  the  foliage  and  fruit  in- 
stead of  taking  place  in  whole  or  in  part  by  way  of  the  roots  and  up 
through  the  stems,  as  supposed  by  Doctor  Halsted,  arises  from  exter- 
nal sources  seems  to  be  proved  by  the  very  satisfactory  results  of 
spraying  experiments  and  by  the  observations  already  recorded.  Sev- 
eral tips  of  vines  bearing  leaves,  collected  September  15,  which  had 
been  thoroughly  sprayed  during  the  season,  were  carefully  washed 
with  corrosive  sublimate  and  placed  in  sterile  moist  chambers.  A 
few  fungi  developed  in  a  very  few  of  these  leaves.  Other  leaves, 
collected  at  the  same  time  from  adjacent  vines  which  had  not  been 
sprayed,  were  treated  in  the  same  manner.  These  were  found  to  be 
completely  infested  with  fungi,  and  the  pycnidia  of  Guignardia  de- 
veloped in  abundance  on  almost  every  leaf. 

A  considerable  quantity  of  fruit  which  had  been  sprayed  was 
treated  in  the  same  manner  as  the  leaves  already  mentioned.  As  a 
result,  1,200  sprayed  berries  picked  on  September  18  showed  on 
October  18  but  9.8  per  cent  of  diseased  fruit,  while  the  same  number 
of  unsprayed  berries  from  the  same  source  kept  under  the  same  con- 
ditions in  the  laboratory  for  the  same  period  showed  38.1  per  cent 
of  diseased  fruit.  The  only  explanation  of  these  results  in  the  light 
of  our  present  knowledge  of  the  effect  of  Bordeaux  mixture  is  that 
most  of  the  spores  of  the  fungus  had  been  destroyed  by  the  spraying 
and  therefore  did  not  gain  entrance  to  the  leaves  and  fruit. 

TREATMENT. 

Applications  to  the  soil. — Acting  upon  the  supposition  that  the 
cranberry-  scald  was  primarily  due  to  unfavorable  soil  conditions  or 
to  fungi  attacking  the  plant  by  way  of  the  root  system,  chemicals 
or  fungicides  to  be  applied  to  the  soil  were  suggested  as  a  remedy 
by  Doctor  Taylor,4  and  later  they  wrere  tried  by  Doctor  Halsted.11 
Lime,  plaster,  salt,  sulphur,  copper  sulphate,  and  iron  sulphate  were 
tried  in  different  quantities.  No  decided  benefit  is  reported  to  have 
resulted  from  these  applications. 

Improving  the  condition  of  the  plants. — It  is  a'  matter  of  general 
observation  that  the  cranberry  scald  is  much  more  serious  on  certain 
bogs  or  portions  of  bogs  than  on  others.  The  conditions  obtaining  in 
the  soil  and  water  of  these  diseased  areas  no  doubt  have  much  to  do 
with  the  prevalence  of  the  disease.  The  factors  concerned  are  so 
complex,  however,  that  it  is  difficult  to  demonstrate  satisfactorily 
exactly  what  they  are  and  which  are  of  greatest  importance.  The 
experience  of  various  growers  appears  to  show  that  the  control  of  the 
no 


TREATMENT.  25 

water  supply  is  an  important  factor.  The  cranberry  plant  is  natu- 
rally water  loving  and  grows  in  its  wild  condition  in  the  sphagnum 
bogs  of  deep  swamps.  When  it  is  cultivated  in  open  meadows  and 
without  a  constant  and  sufficient  water  supply  it  quite  naturally 
becomes  weakened  and  susceptible  to  disease.  In  order  to  keep  the 
plants  in  a  thrifty  condition  the  water  supply  should  not  only  be 
sufficient  but  well  controlled,  so  that  the  moisture  may  be  kept  near 
the  surface  during  the  growing  season.  In  many  cases  there  are  local 
soil  conditions  which  interfere  with  the  healthy  growth  of  the  plants. 

The  practice  of  applying  a  thin  layer  of  sand  to  the  surface  of  the 
bog  every  few  years  is  quite  general  in  Massachusetts  and  is  believed 
to  tend  to  keep  the  plants  in  a  thrifty  and  vigorous  condition.  In 
New  Jersey  this  practice  is  not  so  common  and  the  beneficial  results 
where  it  has  been  tried  do  not  seem  to  have  been  so  apparent  as  in 
Massachusetts.  The  practice  of  sanding,  since  the  sand  would  cover 
all  the  fallen  diseased  leaves  and  many  of  the  old  dead  vines,  would 
tend  to  prevent  the  development  and  spread  of  the  spores  and  might 
prove  beneficial  in  this  way,  if  in  no  other.  It  is  also  desirable  as  a 
sanitary  measure  to  rake  out  and  destroy  all  dead  and  dying  plants. 
The  fungus  Guignardia  vaccinii  produces  its  spores  in  great  abund- 
ance upon  such  plants,  and  these,  therefore,  serve  as  a  source  of  dis- 
tribution for  the  parasite.  All  such  dead  and  diseased  matter  should 
be  destroyed  by  burning,  preferably  in  the  fall  of  the  year. 

Selection  of  resistant  varieties. — It  has  been  frequently  observed 
that  even  in  the  most  diseased  areas  of  cranberry  plants  there  is  an 
occasional  vine  bearing  fruit  which  appears  to  be  free  from  disease. 
It  seems  probable,  therefore,  that  by  the  selection  and  propagation 
of  such  plants  a  variety  might  be  produced  which  would  show  a 
very  considerable  degree  of  resistance  to. this  disease.  As  the  cran- 
berry is  generally  reproduced  by  cuttings,  the  propagation  of  a  re- 
sistant variety  would  be  simpler  and  more  likely  to  succeed  than 
in  the  case  of  plants  propagated  by  seed. 

Application  of  fungicides. — As  already  stated,  Doctor  Halsted  1X 
recommended  spraying  with  ammoniacal  copper  carbonate.  He  also 
reports  4  trying  several  fungicides,  including  Bordeaux  mixture  and 
potassium  sulphid,  making  two  applications  of  each.  No  benefit 
from  these  applications  was  observed. 

After  determining  the  parasitic  nature  of  the  cranberry  scald, 
the  relationship  of  the  parasite,  and  the  probable  manner  of  infec- 
tion, it  seemed  reasonable  that  the  disease  should  be  prevented  by 
the  proper  use  of  fungicides.  In  our  first  experiments  the  ammonia- 
cal copper  carbonate  solution,  potassium  sulphid  solution,  and  Bor- 
deaux mixture  were  used.  As  very  little  benefit  was  apparently 
derived  from  the  use  of  the  two  fungicides  first  mentioned,  later 
352o— No.  110—07  M 4 


26  CKANBEKKY    DISEASES. 

experiments  were  made  with  Bordeaux  mixture  only.  In  the  spray- 
ing work  of  1904  2r>  the  results  showed  an  average  of  21.7  per  cent  of 
diseased  fruit  on  the  sprayed  plats,  while  on  the  unsprayed  check 
plat  there  was  an  average  of  76.8  per  cent  diseased.  The  circum- 
stances under  which  this  was  done  were  such,  however,  that  the  appli- 
cations could  not  be  made  at  proper  intervals.  During  the  next 
season  (190526)  the  work  was  done  more  thoroughly  and  the  results 
were  far  more  satisfactory.  As  a  result  of  five  applications  the 
sprayed  plats  averaged  2.36  per  cent  of  rotten  berries,  while  the  un- 
sprayed check  plats  averaged  92.6  per  cent  of  rotten  fruit.  The 
6-6-50  formula  for  Bordeaux  mixture  was  used  and  4  pounds  of 
resin-fishoil  soap  were  added.  It  was  found  that  the  plain  Bordeaux 
mixture  did  not  spread  properly  over  the  surface  of  the  fruit  and 
foliage,  and  also  did  not  adhere  well.  In  order  to  correct  these 
defects  the  soap  was  added  and  was  found  to  give  most  satisfactory 
results.  The  cost  of  spraying  as  done  in  these  experiments  averaged 
from  $15  to  $20  per  acre,  the  mixture  being  applied  at  the  rate  of 
4  barrels,  or  200  gallons,  at  each  application.  Success  in  preventing 
this  disease  by  spraying  depends  largely  upon  the  care  and  thorough- 
ness with  which  the  preparation  is  made  and  .applied.  In  our  last 
experiments  the  5-5-50  formula  was  used,  and  with  thorough  work 
it  has  been  found  to  give  as  satisfactory  results  as  the  6-6-50  mixture. 

ROT. 

The  term  "  rot "  is  here  applied  to  a  decay  of  the  cranberry  caused 
by  a  fungus  which  we  have  recently  described  as  a  new  genus  and 
species  (Acanthorhynchus  vaccinii  Shear).24  The  appearance  of  the 
fruit  attacked  by  this  disease  is  not  sufficiently  peculiar  or  character- 
istic to  satisfactorily  distinguish  it  from  scald  or  anthracnose  by  its 
external  or  internal  appearance.  The  rot  first  appears  as  a  small, 
light-colored,  soft  spot  on  the  berry,  finally  softening  and  destroying 
the  whole  fruit.  In  the  later  stages  of  its  development  it  very  fre- 
quently produces  small,  dark-colored  blotches  on  the  inner  surface 
of  the  skin.  So  far  as  has  been  observed,  the  fungus  never  produces 
spore-bearing  fructifications  upon  the  berries.  The  only  way  in 
which  this  disease  can  be  positively  diagnosed  is  by  making  a  culture 
from  the  mycelium  of  the  fungus  taken  from  the  interior  of  the 
affected  fruit. 

The  disease  attacks  the  leaves  also,  but  the  fungus  is  very  rarely 
found  in  a  fruiting  condition  except  on  those  which  have  fallen  to 
the  ground.  Judging  from  the  frequency  with  which  this  fungus 
appears  in  cultures  made  by  transplanting  the  fungous  hypha3  from 
decaying  berries,  the  injury  caused  by  it  is  second  only  to  that  pro- 
duced by  the  scald.  Though  this  disease  is  most  frequent  and  destruc- 
no 


THE    FUNGUS    CAUSING    THE    BOT.  27 

t  i  Y(>  in  New  Jersey,  it  has  also  been  found  in  West  Virginia,  Massachu- 
setts, Wisconsin,  and  Nova  Scotia. 

mi:  FUNGUS  (ACANTHORHYNCHUS  VACCINII,  SHEAR)  CAUSING  THE  ROT. 

The  fungus  producing  the  rot  dift'ers  in  several  respects  from  any 
species  which  we  have  been  able  to  find  described.  The  rarity  of  its 
occurrence  in  a  fruiting  condition  in  the  field  probably  accounts  for 
its  not  having  been  discovered  before.  It  has  been  found  occasion- 
ally in  considerable  quantity  on  fallen  leaves  of  diseased  vines,  and 
frequently  appears  on  apparently  healthy  leaves  from  diseased 
vines  which  are  kept  in  a  sterile  moist  chamber  for  a  week  or  two.  It 
grows  readily  on  various  culture  media  and  produces  an  abundance 
of  ascogenous  perithecia. 

Ascogenous  form. — The  perithecia  are  ordinarily  sparsely  scat- 
tered over  the  under  surface  of  the  leaf,  being  buried  beneath  the 
epidermis,  which  is  very  slightly  elevated  and  punctured  by  the  short 
neck  and  ostiole  (PL  III,  fig.  12).  They  usually  vary  in  diameter 
from  300  to  400  /*.  The  short  neck  of  the  perithecium  is  beset  with 
black,  nonseptate  spines  50  to  TO  /x  long  by  8  to  9  ^  thick  at  the  base. 
These  black  spines  are  a  constant  and  characteristic  feature  of  the 
fungus,  occurring  in  all  of  our  cultures,  as  well  as  under  natural 
conditions  (PL  III,  fig.  13).  On  leaves  the  perithecia  are  somewhat 
depressed  globose,  but  in  artificial  cultures,  where  there  is  no 
pressure  from  above  as  there  is  in  the  tissue  of  the  host,  they  are 
somewhat  pyriform.  The  wall  of  the  perithecium  is  membranous  or 
submenbranous  in  texture  and  consists  of  a  single  layer  of  cells.  The 
asci  are  clavate,  short-stipitate,  and  range  in  size  from  136  to  180  by 
30  to  48  p..  They  are  accompanied  by  rather  stout,  sepate  paraphyses, 
occasionally  branched  near  the  end  and  varying  in  dimensions  from 
200  to  340  by  5  to  8  /x.  The  ascospores  are  somewhat  biseriate  or 
irregularly  uniseriate.  They  are  hyaline  until  almost  mature,  but 
finally  assume  a  pale  yellowish  brown  color.  In  shape  they  are 
oblong  elliptical,  and  the  protoplasm  is  densely  granular.  They  vary 
in  size  from  27  to  36  by  12  to  20  p. 

Fruiting  specimens  on  leaves  have  been  collected  in  May,  July, 
August,  September,  and  October,  and  have  been  found  in  Nova 
Scotia,  Massachusetts,  New  Jersey,  West  Virginia,  and  Wisconsin. 

No  conidial  or  pycnidial  form  of  this  fungus  has  ever  occurred  in 
any  of  our  numerous  cultures,  and  no  such  form  has  been  found  asso- 
ciated with  it  in  nature  under  such  circumstances  as  to  suggest  a 
genetic  relation. 

Appressoria. — A  rather  remarkable  body  is  produced  by  the  germ 
tube  of  the  germinating  spore.  This  is  a  more  or  less  disciform, 
dark-colored,  rather  opaque  organ,  with  an  irregular,  rather  deeply 
110 


28  CRANBERRY   DISEASES. 

lobed  margin  (PL  III,  fig.  IT).  It  has  been  found  upon  the  surface 
of  leaves  which  bore  mature  perithecia,  but  was  first  found  on  the 
smooth  surface  of  the  upper  portion  of  culture  flasks  where  spores 
of  the  fungus  had  germinated.  It  is  produced  at  the  end  of  a  short 
germ  tube,  arising  from  the  ascospore,  and  its  primary  function  is 
evidently  that  of  an  apressorium  or  holdfast. 

Appressoria  were  first  described  and  so  named  by  Fisch  37  in  1882, 
as  found  in  Polystigma.  A  little  later  Frank  38  described  the  same 
thing  and  also  the  similar  productions  occurring  in  Gloeosporium 
lindemuthianum.  These  bodies  have  usually  been  called  chlamydo- 
spores.  Meyer,39  De  Bary,40  Bu'sgen,41  and,  more  recently,  Hassel- 
bring,42  have  discussed  these  organs  and  their  formation  and  func- 
tion. Their  production  has  generally  been  regarded  as  due  to  chemi- 
cal or  contact  stimuli  and  lack  of  nutriment.  The  organs  which  are 
produced  by  Acanthorhynchus  vaccinii  differ  in  form  from  any  of 
those  described  by  the  authors  just  mentioned.  They  have  been 
found,  as  already  stated,  on  the  sides  of  glass  culture  flasks  and  upon 
the  surfaces  of  cranberry  leaves.  They  are  produced  in  a  few  hours 
from  fresh  spores  discharged  against  and  adhering  to  the  cover  of  a 
petri  dish.  These  appressoria  when  transferred  to  culture  media 
soon  germinate  and  produce  an  abundance  of  ascogenous  perithecia. 
They  have  also  germinated  on  the  covers  of  petri  dishes  where  they 
have  formed.  This  would  appear  to  indicate  that  they  possess  a 
reproductive  function  not  depending  necessarily  upon  their  connec- 
tion with  the  surface  of  the  host  plant.  When  produced  upon  the 
surface  of  a  cranberry  leaf,  the  small  irregular  projections  about  the 
margin  of  the  disk  appear  to  attach  themselves  firmly,  apparently  by 
dissolving  and  forming  small  shallow  cavities  in  the  surface  of  the 
epidermal  wall.  A  germ  tube  arises  near  the  center,  or  sometimes 
toward  the  margin  of  the  appressorium,  and  penetrates  the  surface 
of  the  leaf,  usually  in  the  sections  we  have  studied  entering  through 
a  stoma  (PI.  Ill,  figs.  21,  22).  Sometimes  the 'germ  tube  does  not 
appear  to  penetrate  the  leaf  at  once,  but  sends  out  several  superficial 
brownish  filaments  upon  the  surface  of  the  leaf,  as  shown  in  Plate 
III,  figure  20.  These  appressoria  have  been  frequently  found  upon 
fallen  cranberry  leaves  during  the  summer.  They  are  sufficiently 
large  to  be  easily  observed,  and  are  so  firmely  attached  to  the  leaves 
that  they  are  not  readily  removed. 

Relationship  of  the  fungus. — Acanthorhynchus  is  evidently  closely 
related  to  certain  Sordariaceous  fungi,  especially  such  genera  as 
Sordaria  and  Hypocopra.  The  perithecia  and  spores  are  somewhat 
similar,  and  the  spores  are  forcibly  discharged  from  the  asci  at 
maturity,  as  in  those  genera.  In  Acanthorhynchus  the  whole  mass 
of  eight  spores  is  thrown  in  some  cases  as  much  as  10  centimeters  or 
no 


THE    FUNGUS    CAUSING    THE   EOT.  29 

more,  and,  being  embedded  in  a  gelatinous  matrix,  they  adhere  to 
any  object  with  which  they  come  in  contact.  As  the  spores  mature 
the  protoplasm  surrounding  them  becomes  denser  and  forms  a  sort  of 
secondary  membrane  (PI.  Ill,  fig.  14,  c).  The  ascus  has  a  character- 
istic apex  which  suggests  that  of  Hypocopra,  as  described  by  Zopf 43 
and  also  by  Griffiths,44  though  in  Acanthorhynchus  it  does  not  turn 
blue  upon  the  application  of  iodin  and  does  not  show  the  peculiar 
thickenings  observed  by  Zopf.  The  mass  of  protoplasm  surrounding 
the  spores  reaches  to  the  apex  of  the  ascus  and  is  attached  there.  In 
the  case  of  some  asci  from  which  the  spores  have  been  discharged  a 
small  caplike  portion  remains,  which  suggests  that  the  ascus  may  rup- 
ture about  the  apex.  In  other  cases,  however,  the  spores  seem  to  have 
been  discharged  through  the  apical  pore  or  the  ascus  has  been  split 
longitudinally  from  the  apical  pore.  It  has  been  impossible  to  differ- 
entiate or  to  positively  distinguish  a  secondary  membrane  about  the 
mass  of  gelatinous  protoplasm  in  which  the  spores  are  embedded, 
but  the  manner  in  which  it  holds  together  would  signify  that  there 
may  be  an  outer  layer  functioning  as  a  secondary  membrane. 

Cultures  of  the  fungus. — Cultures  of  this  fungus  were  first  obtained 
from  mycelium  found  in  the  interior  of  rotten  berries.  These  cul- 
tures were  made  by  transplanting  the  mycelium  as  described  in  the 
case  of  Guignardia  vaccinii.  Perfect  perithecia  and  asci  have  been 
produced  in  forty  different  cultures  made  from  diseased  berries. 
In  a  number  of  instances  a  mycelium  apparently  identical  with  that 
of  Acanthorhynchus  has  appeared,  but  no  perithecia  were  ever 
formed.  The  fungus  grows  and  reproduces  most  readily  on  corn 
meal,  corn  meal  agar,  and  cranberry  agar  and  corn  meal.  A  few 
mature  perithecia  have  been  formed  on  steamed  sweet  potato  cylin- 
ders. The  fresh  ascospores  sometimes  germinate  quickly  in  moist 
air  and  produce  appressoria  in  a  few  hours.  In  most  cases  in  which 
spores  have  been  observed  to  germinate,  appressoria  have  been 
formed.  The  spores  very  rarely  germinate  in  culture  media. 
They  germinate  in  damp  air  or  water  on  glass  and  also  on 
cranberry  leaves.  In  pure  cultures  the  fungus  first  forms  a  branched 
white  mycelium,  which  spreads  concentrically  from  the  point  of 
origin,  forming  a  rather  close  white  layer,  which  continues  to 
spread  until  the  whole  surface  of  the  culture  medium  is  covered. 
Soon  the  mycelium  begins  to  assume  a  dirty,  ochraceous  color,  which 
becomes  quite  uniform  and  is  soon  followed  by  the  appearance  of  the 
dark  perithecia  of  the  fungus.  These,  when  full  grown,  give  a  dark 
cast  to  the  surface  as  they  become  uniformly  distributed  throughout 
the  yellowish  layer.  As  in  case  of  other  ascogenous  forms  Avhose 
natural  mode  of  growth  is  within  the  tissues  of  their  host,  the  peri- 
thecia in  cultures  are  more  or  less  covered  with  fungous  hyphse,  with 
no 


30  CRANBERRY    DISEASES. 

the  exception  of  the  short  neck,  which  protrudes  above  the  surface 
of  the  mycelial  subiculum  (PL  III,  fig.  13).  The  fungus  grows  best  at 
ordinary  laboratory  temperatures,  varying  from  20°  to  26°  C.,  and 
the  mature  perithecia  are  produced  iri  from  fourteen  to  thirty  days. 
As  in  the  case  of  Guignardia,  and  for  the  same  reasons,  we  have  been 
unable  to  determine  yet  at  what  time  infection  of  fruit  and  vines 
takes  place.  Appressoria  have  not  been  observed  on  diseased  berries, 
but,  as  already  stated,  they  have  been  found  on  leaves,  with  the  germ 
tube  penetrating  the  tissue.  The  fungus  is  found  in  a  fruiting  condi- 
tion on  the  cranberry  bogs  soon  after  the  water  is  removed  from  the 
vines  in  the  spring.  It  is  therefore  probable  that  infection  of  the 
young  leaves  begins  about  this  time. 

This  fungus  also  evidently  has  the  power  of  remaining  in  a  dor- 
mant or  inactive  condition  in  the  leaves  and  fruits,  as  is  shown  by  the 
development  of  the  fungus  in  apparently  normal  and  healthy  leaves 
and  fruits  wThich  have  been  disinfected  and  kept  in  moist  chambers  in 
the  laboratory.  That  the  original  infection  is  from  external  sources 
is  shown  by  the  presence  of  appressoria  on  the  leaves,  the  germ  tubes 
of  which  have  been  found  entering  the  tissue  (PL  III,  fig.  22). 

TREATMENT. 

What  has  been  said  in  regard  to  the  treatment  of  cranberry  scald 
applies  equally  well  to  the  rot.  The  two  diseases  almost  always  occur 
together,  and  Bordeaux  mixture  applied  in  the  same  manner  as  for 
scald  has  given  satisfactory  results. 

ANTHRACNOSE. 

Anthracnose  is  a  disease  not  heretofore  reported  as  affecting  the 
cranberry.  As  is  the  case  in  most  other  diseases  to  which  this  name 
is  applied,  it  is  due  to  one  of  the  fungi  which  have  been  called  Gloeo- 
sporium.  The  ascogenous  stage  of  the  fungus  having  been  produced, 
it  is  found  to  belong  to  the  genus  Glomerella  and  has  been  named 
Glomerella  rufomaculans  vaccinii  Shear.24  Like  the  scald  and  rot, 
this  disease  is  at  all  times  difficult,  and  usually  impossible,  to  diag- 
nose by  a  macroscopic  examination  of  the  diseased  berries.  The 
berries  from  which  wre  have  isolated  the  fungus  which  causes  this 
disease  have  not  been  uniform  in  appearance.  In  one  case  the  berry 
was  very  soft  and  light  colored,  while  in  other  cases  the  fungus  did 
not  seem  to  have  developed  so  rapidly  and  the  portion  of  the  fruit 
affected  by  the  disease  was  not  so  soft.  Acervuli  sometimes  develop 
on  the  diseased  berry,  but  usually  they  do  not.  Judging  from  the 
infrequency  of  occurrence  of  this  fungus  in  cultures  made  from 
affected  berries,  the  disease  is  much  less  injurious  than  the  rot  or 
no 


THE    FUNGUS    CAUSING    ANTHRACNOSE.  31 

scald.  It  appears,  however,  to  be  widely  and  generally  distributed 
throughout  the  cranberry  growing  regions  of  the  eastern  United 
States. 

THE    FUNGUS     (  GLOMERELLA    RUFOMACULANS    VACCINII,    SHEAR)     CAUSING 

ANTHRACNOSE. 

Two  species  of  Gloeosporium  have  already  been  described  as  occur- 
ring upon  species  of  Vaccinium,  but  their  relation  to  the  fungus 
causing  this  disease  is  doubtful.  This  parasite  has  been  grown  in 
pure  cultures,  producing  both  the  conidial  and  ascogenous  forms. 

Conidial  form. — The  acervuli  are  rather  small,  scattered  over  the 
under  or  upper  surface  of  the  leaf  and  sometimes  occurring  upon  old 
berries  which  have  been  destroyed  by  the  fungus.  The  epidermis  is 
usually  somewhat  dark  colored  immediately  above  and  about  the 
mass  of  conidia.  At  maturity  the  epidermis  ruptures  and  the  conidia 
form  a  light,  flesh-colored,  waxy  mass  upon  the  surface.  They  are 
hyaline  or  subhyaline,  as  observed  under  the  microscope,  and  oblong 
elliptical,  or  sometimes  slightly  smaller  at  one  end,  varying  in  dimen- 
sions from  12  to  18  by  4.5  to  6  /x  (PL  III,  fig.  2).  The  conidiophores 
are  simple,  tapering  upward,  and  from  15  to  20  /x  long.  The  conidia 
germinate  readily  in  water  or  ordinary  culture  media.  The  mode 
of  germination  and  growth  agrees  with  that  of  other  species  of 
Gloeosporium,  as  described  by  Stoneman,45  Clinton,46  and  others, 
except  that  no  septum  is  formed  in  the  conidia  so  far  as  observed. 
This  conidial  form  has  been  found  on  berries  from  several  localities 
in  Massachusetts,  and  also  on  leaves  from  New  Jersey  which  were 
soaked  in  corrosive  sublimate  1-1,000  and  kept  in  a  moist  chamber 
for  from  one  to  two  weeks.  It  has  also  been  obtained  in  cultures 
made  from  diseased  fruit  from  Wisconsin,  Massachusetts,  and  New 
Jersey. 

Ascogenous  form. — This  stage  of  the  fungus  has  not  been  found 
on  the  cranberry  plant  either  in  the  field  or  in  moist  chambers,  but 
has  been  grown  in  cultures  from  leaves  bearing  the  fungus,  and  also 
from  ascospores.  The  perithecia  are  membranous,  subglobose  or 
slightly  pear  shaped,  usually  somewhat  buried  in  a  felty  subiculum 
or  pseudo-stroma  when  growing  on  corn  meal  and  forming  a  continu- 
ous layer  over  its  surface  (PI.  Ill,  fig.  6).  In  old  cultures  they  fre- 
quently become  closely  packed  and  form  a  more  or  less  opaque  stra- 
tum. The  asci  are  clavate,  sessile,  or  short  stipitate,  and  measure  60 
to  72  by  10  to  12  /A  (PL  III,  fig.  7,  a,  £,  <?),  and  are  sometimes  accom- 
panied by  what  seem  to  be  evanescent  paraphyses  (PL  III,  fig.  9). 
The  ascospores  are  somewhat  irregularly  biseriate,  oblong  elliptical, 
and  occasionally  slightly  inequilateral  or  curved.  They  are  hyaline 
no 


32  CRANBERRY    DISEASES. 

at  first,  but  when  fully  mature  become  pale  greenish  yellow.  They 
vary  in  size  from  9  to  18  by  5  to  7.5  /*  (PL  III,  fig.  8). 

Appressoria^  or  chlamydospores. — In  badly  decayed  berries  and  in 
old  pure  cultures  the  irregular  dark-colored  bodies  have  been  found 
which  have  been  called  chlamydospores  by  some  authors  and  appres- 
soria  by  others  (PL  III,  figs.  4  and  5) .  The  work  of  Fisch,37  Frank,38 
Hasselbring,42  and  others  seems  to  show  that  the  primary  function 
of  these  organs  is  that  of  an  appressorium.  In  the  case  of  the 
cranberry  anthracnose,  at  least,  they  may  also  function  as  repro- 
ductive bodies.  Some  of  those  found  in  the  interior  of  a  decayed 
berry  (PL  III,  fig.  4)  were  carefully  transferred  to  culture  media 
and  were  found  to  germinate  and  produce  a  luxuriant  growth  of 
mycelium  and  conidia.  It  has  been  urged  that  they  show  no  pro- 
vision for  distribution,  as  spores  or  reproductive  bodies  should. 
When  produced  in  the  interior  of  berries,  however,  the}7  appear  to 
show  even  less  possibility  of  functioning  as  appressoria.  The  bodies 
as  found  in  fruit  and  old  cultures  are  somewhat  variable  in  form 
and  appearance,  but  agree  in  general  with  those  produced  upon  the 
germ  tubes  arising  from  conidia.  The  light-colored  spot  frequently 
observed  and  regarded  by  some  as  a  germ  pore  is  quite  as  frequently 
wanting  in  the  cases  we  have  observed.  Though  probably  primarily 
functioning  as  appressoria,  these  bodies  under  certain  conditions 
appear  to  serve  the  purpose  of  a  resting  spore  or  chlamydospore. 

Cultures  of  Glomerella  rufomaculans  vaccinii. — Cultures  made 
from  berries  affected  with  anthracnose  and  from  leaves  have  in  most 
cases  produced  conidia  only,  but  in  four  instances  the  ascogenous 
stage  was  also  produced.  The  berries  were  from  Massachusetts,  New 
Jersey,  and  Wisconsin. 

Cultures  have  also  been  made  from  leaves  containing  mycelium  as 
well  as  from  conidia  and  ascospores.  The  growth  in  all  cases  is 
essentially  the  same  in  appearance.  The  conidia  germinate  readily, 
sending  forth  one  or  more  germ  tubes,  which  soon  begin  to  branch 
and  then  form  a  rather  dense  pure  white  mycelium.  This  on  steril- 
ized corn  meal  spreads  rapidly  until  the  surface  of  the  medium  is 
covered  with  a  compact  layer  of  the  fungus.  On  poured  plates  of 
beef  agar  the  growth  of  the  mycelium  is  much  less  luxuriant. 
Acervuli  of  conidia  begin  to  appear  in  three  or  four  days,  and  these 
are  frequently  followed  by  the  formation  of  dark-colored  bodies 
resembling  the  fundaments  of  perithecia.  These  bodies,  however, 
have  never  produced  mature  asci  on  agar  cultures. 

The  germination  of  the  ascospores  and  the  subsequent  growth  and 

development  of  the  mycelium  are  essentially  the  same  as  in  the  case 

of  the  conidia.     Cultures  from  ascospores  on  poured  plates  of  beef 

^agar  only  produced  conidia  and  what  appeared  to  be  young  perithe- 

110 


THE    FUNGUS    CAUSING    ANTHRACNOS$.  33 


cia,  but  no  asci  were  ever  found.  Transfers  made  of  germinating 
ascospores  from  such  poured  plates  to  flasks  of  sterilized  corn  meal 
produced  ascogenous  perithecia  in  abundance  in  about  ten  to  twelve 
days.  In  the  case  of  one  culture  made  from  a  diseased  berry,  very 
few  conidia  were  ever  formed,  but  an  abundance  of  the  ascogenous 
form  was  present  after  eighteen  days.  We  have  not  as  yet  succeeded 
in  growing  the  ascogenous  form  in  pure  cultures  from  single  conidia. 
Little  opportunity,  however,  has  been  given  for  making  such  cultures 
from  the  ascus-bearing  form,  on  account  of  the  few  conidia  produced 
by  it.  Besides  beef  agar  and  corn  meal,  the  fungus  has  been  grown 
upon  cranberry  agar  and  com  meal,  and  also  upon  potato  cylinders. 
Although  the  fungus  appears  to  grow  best  on  corn  meal  or  cranberry 
agar  and  corn  meal,  there  is  nothing  to  indicate  that  the  culture 
medium  is  the  determining  factor  in  the  production  of  the  ascogenous 
stage  of  the  fungus.  As  in  the  case  of  the  scald  fungus,  Guignardia 
vaccinii,  the  important  factor  seems  to  be  some  particular  potentiality 
of  the  mycelium  or  spore  from  which  the  culture  is  made. 

Factors  determining  the  production  of  the  ascogenous  fructifica- 
tion.— Previous  successful  attempts  of  the  writer  and  others  to  pro- 
duce asci  in  various  forms  of  Gloeosporium  have  indicated  that  there 
is  a  much  more  important  factor  involved  than  the  culture  medium  or 
conditions  of  light,  temperature,  and  moisture.  Whether  the  near- 
ness or  remoteness  of  origin  of  the  conidia  from  an  ascogenous  form 
is  of  importance  has  not  yet  been  satisfactorily  determined.  The 
successful  cultures  made  by  Miss  Stoneman 45  were  from  conidia 
taken  from  acervuli  produced  upon  the  different  hosts  of  the  species 
studied.  In  such  cases,  of  course,  there  is  no  means  of  determining 
the  ancestry  of  the  conidia  used. 

Relationship  of  the  fungus. — The  ascogenous  forms  of  the  numer- 
ous anthracnoses  known  have  very  rarely  been  recognized  or  reported 
as  occurring  under  natural  conditions.  It  is  probable,  however,  that 
some  of  the  pyrenomycetous  fungi  which  have  been  described  under 
the  genera  Physalospora  or  Phomatospora,  or  perhaps  under  other 
closely  related  genera,  are  really  the  ascogenous  forms  of  species 
of  Gloeosporium.  The  very  close  relationship  of  many  of  the  species 
described  under  these  genera  and  the  want  of  any  very  striking  or 
peculiar  characteristics  of  the  known  ascogenous  forms  of  Gloeospo- 
rium make  it  difficult  to  determine  with  certainty  from  purely  mor- 
phological characters  the  generic  identity  of  these  organisms.  The 
name  Glomerella  has  been  proposed  for  these  fungi  by  Spaulding 
and  von  Schrenk.47  This  name,  however,  may  have  to  be  abandoned 
if  it  can  be  demonstrated  that  ascogenous  forms  heretofore  described 
under  an  older  valid  generic  name  are  really  stages  in  the  develop- 
ment of  congeneric  species.  The  question  of  specific  distinctions  in 
no 


34  CEANBEERY    DISEASES. 

this  genus  is  very  perplexing.  The  differences  in  the  morphological 
characters  of  the  ascogenous  fructifications  are  quite  as  slight  and 
unsatisfactory  for  separating  species  as  the  differences  which  occur 
in  the  conidial  forms.  This  has  been  clearly  shown  by  the  studies  of 
Shear  and  Woods.35  Various  inoculation  experiments  made  with  the 
conidial  forms  occurring  on  different  hosts  have  seemed  to  indicate 
that  they  will  pass  readily  from  one  host  to  another.  Most  such 
inoculation  experiments  appear  to  us  inconclusive,  particularly  in 
such  cases  as  those  given  by  Halsted  14  and  others,  in  which  transfers 
of  conidia  were  made  from  one  mature  fruit  to  another  by  inserting 
the  conidia  in  the  fruit.  These  experiments  may  perhaps  be  more 
correctly  interpreted  as  indicating  that  the  fruit  upon  which  the 
fungus  grows  successfully  in  such  an  inoculation  experiment  is 
simply  a  satisfactory  nutrient  medium  for  the  fungus.  In  order  to 
demonstrate  the  possibility  of  the  various  forms  being  passed  from 
one  host  to  another  as  actual  parasites,  it  would  be  necessary  to  make 
the  inoculations  on  the  living  and  actively  growing  parts  of  the 
plants.  This  has  been  done  in  one  case,  at  least,  by  Sheldon,48  in 
which  he  successfully  inoculated  stems  and  leaves  of  growing  sweet 
peas  by  applying  conidia  from  the  bitter-rot  (Glomerella  rufomacu- 
lans  (Berk.)  Spauld.'  &  von  Schrenk)  of  the  apple.  Whether  other 
forms  will  show  equal  ability  to  pass  from  one  host  to  another  as 
active  parasites  remains  to  be  determined. 

Dormant  condition  of  the  fungus. — We  have  found  by  experiments 
similar  to  those  described  in  connection  with  the  account  of  the 
scald  fungus,  Guignardia  vaccinii  (p.  21),  that  the  mycelium  of  the 
cranberry  Glomerella  may  remain  in  an  inactive  or  dormant  condition 
in  the  tissues  of  the  living  fruit  of  the  cranberry  for  a  considerable 
time.  Whether  the  fungus  is  really  inactive  or  not  it  is  difficult  to 
say.  It  at  least  does  not  give  the  slightest  local  external  evidence  of 
its  presence.  Berries  which  were,  so  far  as  could  be  determined  by 
external  examination,  perfectly  sound  and  free  from  fungi,  were  very 
thoroughly  soaked  and  washed  in  a  1-500  solution  of  corrosive  sub- 
limate. Such  leaves  and  berries  when  placed  in  warm,  sterile,  moist 
chambers  developed  typical  cases  of  anthracnose.  On  the  leaves 
treated  in  the  same  manner  numerous  acervuli  have  appeared, 
and  cultures  made  from  the  mycelium  found  in  the  decayed  fruits 
mentioned  above  have  produced  the  conidia  in  pure  cultures.  Inoc- 
ulation experiments,  made  by  applying  fresh  conidia  to  the  surface 
of  cranberries  and  apples  placed  in  warm  moist  chambers,  have  been 
without  definite  results.  It  seems  that  in  the  case  of  this  fungus,  as 
well  as  Acanthorhynchus  and  Guignardia,  the  spores  do  not  pos- 
sess the  power  of  penetrating  the  epidermis  of  the  fruit  after  it  has 
reached  maturity.  Infection  apparently  occurs  earlier  in  the  season, 
no 


HYPERTROPHY.  35 

but  the  exact  time  and  manner  has  not  yet  been  determined  for  want 
of  plants  known  to  be  entirely  free  from  disease. 

TREATMENT. 

From  the  beneficial  results  of  spraying  cranberries  where  this  dis- 
ease was  known  to  be  present  and  also  from  the  success  obtained  in 
preventing  other  diseases  caused  by  similar  fungi,  such  as  the  bitter- 
rot  fungus  of  the  apple,49  it  appears  probable  that  thorough  spray- 
ing with  Bordeaux  mixture  will  prove  a  satisfactory  treatment. 
The  disease  so  far  as  now  known  is  always  associated  with  scald  or 
rot,  and  the  treatment  recommended  for  those  diseases  will  be  suffi- 
cient for  this. 

HYPERTROPHY. 

The  fungus  (Exobasidium  oxy cocci  Rostr.)  causing  hypertrophy  is 
only  known  at  present  from  Massachusetts.  In  1906  it  destroyed  a 
considerable  part  of  the  crop  on  several  cranberry  meadows  in  that 
State  and  caused  considerable  alarm.  It  is  apparently  somewhat 
erratic  in  its  behavior.  On  one  meadow  it  attacked  almost  every 
plant  on  a  part  of  the  bog,  while  some  other  portions  were  almost  free 
from  it.  The  variety  known  as  Matthews  seemed  to  be  especially 
susceptible  to  the  disease. 

The  disease  first  makes  its  appearance  on  flooded  bogs  soon  after 
the  water  has  been  removed  in  the  spring,  which  is  usually  about  the 
middle  of  May  or  a  little  later.  The  axillary  leaf  buds,  which  usually 
remain  dormant,  are  attacked  by  the  disease  and  produce  short  shoots 
with  rather  close,  enlarged,  swollen,  and  distorted  leaves  which  are 
pink  or  light  rose  colored  (PI.  VII,  C  and  D).  The  colored  Iwper- 
trophied  leaves,  being  close  together,  bear  a  slight  superficial  resem- 
blance to  a  flower  of  some  sort.  This  appearance  has  led  some  per- 
sons to  call  these  diseased  shoots  "  false  blossoms."  This  is  mislead- 
ing, as  it  suggests  some  reference  to  the  flowers  of  the  cranberry, 
which  are  not  included  in  this  peculiar  malformation. 

Most  of  the  affected  plants  are  attacked  before  the  blossoms  have 
developed,  thus  preventing  the  production  of  fruit.  Shoots  whose 
buds  are  attacked  later  in  the  season  after  the  blossoms  have  opened 
or  fallen  (PL  VII,  D)  also  usually  fail  to  develop  fruit,  as  the  vital- 
ity of  the  shoot  is  apparently  exhausted  by  the  fungus.  Besides  the 
fruit-bearing  shoots,  ordinary  vegetative  shoots  or  runners  are  also 
affected  in  the  same  manner  (PL  VII,  C). 

No  opportunity  has  been  afforded  to  examine  plants  which  had 
suffered  from  this  disease  the  previous  year,  but  the  injury  to  the 
affected  plants  and  the  lowering  of  their  vitality  are  so  evident  that 
the  production  of  fruit  the  succeeding  season  would  probably  be  far 
below  normal  even  though  the  disease  did  not  recur  upon  the  plants, 
no 


36  CEANBEKRY   DISEASES. 

THE   FUNGUS    (EXOBASIDIUM    OXYCOCCI,  ROSTR.)    CAUSING    HYPERTROPHY. 

In  this,  like  all  Exobasidii,  the  mycelium  of  the  fungus  infests 
the  tissue  of  the  leaves  and  stems,  producing  the  hypertrophied  con- 
dition described  above.  The  basidia  are  elongate  clavate,  and  are 
produced  at  the  extremities  of  the  hyphas.  They  emerge  on  the 
surface  of  the  affected  part  of  the  host  and  produce  usually  four 
basidiospores  at  the  ends  of  short,  slender  sterigmata.  The  spores 
are  usually  somewhat  fusiform,  slightly  curved,  and  hyaline,  measur- 
ing 14  by  3.5  fji.  They  proceed  to  grow  soon  after  falling  and  may 
be  seen  in  old  specimens  in  different  stages  of  germination.  From 
one  to  three  transverse  septa  are  usually  formed,  after  which  a  germ 
tube  arises  from  either  or  both  ends,  which  produces  conidia  somewhat 
resembling  the  basidiospores,  but  smaller.  The  fungus,  when  mature, 
gives  a  fine,  gray,  powdery  appearance  to  the  surface  of  the  distorted 
parts  of  the  host. 

Relationship  to  other  Exobasidii. — This  species,  so  far  as  it  has 
been  studied,  agrees  in  morphological  characters  with  Exobasidium 
vaccinii  (Fckl.)  Wor.  The  spores  of  Exobasidium  vaccinii  are, 
according  to  Saccardo,  5  to  8  by  1  to  2  /x.  This,  according  to 
Woronin,9  Richards,59  and  others,  is  an  error,  as  the  basidio- 
spores usually  range  from  14  to  17  by  3  /*.  The  error  possibly  arose 
from  the  confusion  of  basidiospores  with  conidia,  which  are  fre- 
quently present,  especially  in  specimens  which  are  getting  old. 

The  typical  form  of  Exobasidium  vaccinii  occurs  on  Vaccinium 
vitis-idaea,  producing  hypertrophied  spots  on  the  leaves.  No  record 
has  been  found  of  the  occurrence  of  hypertrophied  shoots  on  this 
host  similar  to  those  found  on  cranberry  plants.  Rostrup  51  seems 
to  have  been  the  first  to  describe  this  form.  In  1883  he  reported  it 
as  occurring  on  Oxy coccus  palustris  in  Denmark.  His  description 
accords  exactly  with  the  specimens  we  have  found  on  the  cranberry 
plant.  He  says  he  could  not  find  the  two  forms,  i.  e.,  the  one  pro- 
ducing spots  on  the  leaves,  typical  Exobasidium  vaccinii,  and  the  one 
producing  hypertrophied  shoots,  Exobasidium  oxycocci,  on  the  same 
plant,  but  the  two  were  found  in  the  same  locality  in  one  instance. 

An  Exobasidium  also  occurs  on  cranberry  plants  in  Massachu- 
setts, which  produces  spots  on  the  leaves  like  those  produced  on 
Vaccinium  vitis-idaea,  and  agrees  also  in  all  microscopical  characters 
with  Exobasidium  vaccinii  (Fckl.)  Wor.  (PL  VII,  A  and  B).  No 
specimens  of  the  two  forms  could  be  found  on  the  same  plant  or 
in  the  same  vicinity.  No  cross-infection  experiments  with  these  two 
forms  have  been  tried  on  these  hosts  so  far  as  known,  and  as  the 
observations  already  made  seem  to  indicate  the  probability  of  their 
no 


LESS    IMPORTANT    DISEASES.  37 

being  separate  species,  we  shall  retain  for  the  present  the  two  names 
as  already  used. 

Richards 59  reports  infection  experiments  with  the  Exobasidium 
producing  spots  on  leaves  of  Andromeda  and  the  one  forming  large 
inflated  galls  on  the  same  host.  He  succeeded  in  producing  the  leaf- 
spot  form  by  using  spores  from  the  gall-producing  form  which  was 
named  Exobasidium  andromedae  by'  Peck.03  This  suggests  the  pos- 
sibility of  the  interchange  of  other  forms,  and  it  is  hoped  that  further 
work  may  be  done  in  this  direction. 

Exobasidium  oxycocci  occurs  in  greatest  abundance  in  May  and 
June.  It  has  also  been  collected  as  late  as  September,  when  occasional 
fresh  specimens  were  found  at  Brewster  and  Pleasant  Lake,  Mass. 

TREATMENT. 

Little,  if  anything,  so  far  as  can  be  learned,  has  been  attempted 
in  the  way  of  controlling  diseases  caused  by  Exobasidii,  as  they 
have  rarely  assumed  economic  importance.  As  definite  knowledge  in 
regard  to  time  and  manner  of  infection  is  lacking,  it  is  difficult  to 
recommend  treatment.  It  is  possible  that  spraying  with  Bordeaux 
mixture  may  be  beneficial,  and  experiments  in  this  direction  are 
planned  for  the  coming  season,  when  it  is  also  hoped  to  secure  more 
knowledge  of  this  fungus. 

LESS   IMPORTANT   DISEASES. 
FUNGI    ATTACKING    THE    FRUIT. 

8ynchytrium  vaccinii  Thomas. — This  fungus  was  first  described 
from  New  Jersey  specimens  by  Dr.  Fr.  Thomas,5'5  of  Germany,  in 
March,  1889,  under  the  above  name.  When  first  discovered  it  threat- 
ened to  do  serious  injury  to  the  New  Jersey  cranberry  bogs.  It  was 
first  found  in  1886  upon  a  bog  near  Browns  Mills,  N.  J.  Doctor 
Halsted,10  of  the  New  Jersey  Experiment  Station,  gave  an  account 
of  the  disease  in  1880,  and  called  the  parasite  the  cranberry  gall 
fungus.  The  fungus  attacks  the  leaAres  and  young  stems  as  well  as 
the  flowers  and  fruit,  forming  great  numbers  of  small,  reddish, 
gall-like  swellings  upon  their  surface  (PL  IV,  figs.  15  and  16).  Sec- 
tions of  these  galls  show  the  fructification  of  the  fungus  embedded 
near  their  center  (PL  IV,  fig.  17).  The  fungus  consists  of  a  scanty 
vegetative  mycelium  producing  globose  sporangia,  which  finally 
develop  a  mass  of  swarm  spores  within.  The  sporangia  rupture  and 
the  spores  are  then  set  free.  These  swarm  spores  are  motile  and  well 
adapted  to  distribution  through  the  water.  At  the  time  this  fungus 
was  found  at  the  place  mentioned  a  considerable  portion  of  the 
plants  on  one  side  of  the  cranberry  meadow  was  affected  and  the 
no 


88  CRANBERRY   DISEASES. 

complete  destruction  of  the  vines  was  threatened.  So  far  as  known 
the  only  measure  taken  to  prevent  the  disease  was  the  withholding 
of  the  water  during  the  winter,  as  it  was  believed  that  the  disease  was 
distributed  chiefly  by  the  water.  This  plan  seems  to  have  proved 
successful,  as  the  disease  disappeared  entirely  within  a  few  years. 
When  the  affected  bog  was  recently  visited  it  was  impossible  to  find 
a  trace  of  the  fungus  present  on  the  vines  or  to  learn  of  its  occurrence 
anywhere  in  the  region  since.  It  seems  to  have  entirely  disappeared." 
Similar  sudden  appearances  of  new  parasites  have  been  observed.  No 
entirely  satisfactory  explanation  of  such  phenomena  has  yet  been 
given.  Their  sudden  disappearance  is  less  common.  This  fungus  is 
not  restricted  to  the  cranberry  plant,  but  has  been  found  on  several 
other  ericaceous  plants.  Specimens  on  the  following  hosts  collected  by 
Doctor  Halsted  in  New  Jersey  are  preserved  in  the  pathological  col- 
lections of  the  Department :  Gaultheria  procumbens,  Cassandra  caly- 
culata,  Kalmia  angustifolia,  Azalea  viscosa,  Clethra  alnifolia,  and 
Gaylussacia  sp.  It  may  be  expected  to  appear  again  if  the  condi- 
tions for  its  development  and  spread  should  happen  to  be  favorable. 
Since  its  discovery  in  New  Jersey  it  has  been  found  as  far  north  as 
Newfoundland,  but  has  not  been  reported  as  doing  harm  to  the  cran- 
berry, except  in  the  case  mentioned. 

Pestalozzia  guepini  vaccinii  Shear.22-r-This  fungus  has  been 
isolated  in  eight  instances  from  diseased  cranberries.  It  is  also 
frequently  found  on  the  leaves  of  the  cranberry  plant.  The  effect  of 
this  fungus  upon  the  berries,  like  that  of  some  other  parasites,  is  not 
sufficiently  characteristic  to  enable  one  to  recognize  it  by  an  examina- 
tion of  the  fruit.  Hence  we  are  unable  to  determine  how  much  injury 
is  caused  by  it.  The  indications  are,  however,  that  it  does  not  do 
nearly  as  much  damage  as  the  other  parasites  already  described.  It 
is  much  more  frequent  upon  the  leaves  than  upon  the  berries  and 
may  be  found  upon  the  recently  fallen  leaves  during  the  summer.  It 
also  develops  very  frequently  on  leaves  apparently  free  from  disease 
when  they  are  placed  in  a  sterile  moist  chamber. 

The  acervuli  of  the  fungus  are  formed  beneath  the  epidermis  and 
are  sparsely  scattered  over  the  leaf  (PI.  II,  fig.  15).  As  the  fungus 
matures  the  epidermis  ruptures  and  the  spores  collect  in  dark  masses 
or  spread  out  and  form  a  thin  layer  upon  the  surface  about  the 
acervuli.  The  corridia  are  elliptical  and  somewhat  inequilateral  and 
usually  four-septate  (PL  II,  fig.  15,  <z,  5).  The  three  central  cells  are 
dark  colored  and  usually  guttulate.  The  septum  below  the  upper  cell 
is  usually  darker  than  the  others.  The  two  terminal  cells  are  hyaline, 
and  the  apical  one  is  furnished  with  three  to  four  filiform  setae, 

°  Since  this  was  written  the  disease  has  again  been  reported  as  occurring  this 
season  in  New  Jersey. 
HO 


LESS    IMPORTANT    DISEASES.  39 

varying  from  22  to  35  /x  in  length.  The  basal  cell  also  has  a  short 
hyaline  appendage  6  to  12  /A  long. 

This  fungus  is  quite  generally  distributed  in  the  cranberry-growing 
regions.  Specimens  have  been  obtained  from  West  Virginia,  New 
Jersey,  Wisconsin,  Massachusetts,  and  New  York. 

Pestalozzia  guepini  Desm.  is  given  by  Farlow  and  Seymour60  as 
occurring  on  the  cranberry,  but  a  study  of  that  species  indicates  that 
our  plant  is  a  variety  at  least,  as  indicated,  and  may  perhaps  be 
found  to  be  a  distinct  species. 

The  spores  of  this  fungus  germinate  readily  under  ordinary  labo- 
ratory conditions  in  water  or  culture  media.  The  germ  tube  almost 
invariably  arises  from  the  basal  cell  of  the  spore  (PL  II,  fig.  15,  c,  d). 
Occasionally  two  germ  tubes  arise,  one  from  each  side  of  the  basal  cell 
(PL  II,  fig.  15,  d).  The  germ  tube  grows  rapidly  and  soon  begins  to 
branch,  forming  a  nearly  white  mycelium.  This  covers  the  culture 
medium  with  a  thin,  rather  compact  layer.  About  the  time  acervuli 
begin  to  form,  a  faint  pinkish  tinge  appears.  Acervuli  and  spores  are 
produced  in  about  ten  to  twelve  days.  The  acervuli  first  appear  as 
dark-colored  dots.  Spores  are  produced  in  enormous  numbers  and 
spread  about  the  acervuli  in  irregular  black  masses. 

This  fungus  has  been  grown  from  leaves  and  fruit  from  different 
sources  on  different  media  and  under  different  conditions  for  several 
years,  but  no  other  spore  form  has  ever  been  found.  Where  the 
growth  of  the  fungus  is  very  luxuriant,  abnormal  spores  are  pro- 
duced, which  bear  four  or  five  and  rarely  six  appendages,  sometimes 
much  longer  than  usual,  and  branched. 

This  fungus  is  common  and  widely  distributed,  but  so  far  as  our 
knowledge  goes  does  not  attack  the  fruit  with  sufficient  frequency  to 
cause  much  loss.  It  is  much  more  common  on  the  foliage  and  may  thus 
injure  the  plants  affected.  It  has  been  found  to  be  present  in  leaves 
which  showed  no  external  signs  of  disease,  as  has  already  been  noted 
in  the  case  of  Guignardia  vaccinii  and  some  of  the  other  cranberry 
fungi. 

There  is  reason  to  believe  that  where  the  disease  is  present  it  can 
be  controlled  by  the  usual  treatment  with  Bordeaux  mixture. 

Helminthosporium  inaequalis  Shear 24. — This  fungus  has  been 
obtained  in  cultures  made  from  diseased  cranberries  from  New  Jer- 
sey. These  cultures  were  made  November  8,  1905,  by  carefully  trans- 
ferring the  fungous  hyphse  from  the  pulp  of  affected  berries  to  flasks 
containing  sterilized  corn  meal.  There  was  nothing  in  the  external 
appearance  of  these  berries  to  indicate  that  the  injury  was  due  to 
other  than  the  usual  rot  or  scald  fungi.  The  first  growth  of  the 
mycelium  was  nearly  white,  but  very  soon  assumed  a  light,  smoky 
color,  and  finally  became  a  dark,  smoky  brown.  The  whole  surface 

110 


40  CRANBEKRY    DISEASES. 

of  the  medium  was  covered  with  a  thick,  loose  layer  of  much-branched 
hyphse.  The  vegetative  hyphse  frequently  form  strands  of  several 
filaments  closely  united  (PL  V,  fig.  8). 

The  fertile  hypha?  were  distributed  over  the  surface  and  bore 
conidia  at  the  apex  as  well  as  at  the  sides  (PL  V,  fig.  4).  These 
conidia  are  somewhat  elliptical  and  usually  conspicuously  inequilat- 
eral (PL  V,  figs.  5,  6,  7).  They  are  thick  walled  and  from  three  to 
five  celled  at  maturity,  all  but  the  terminal  cells,  which  are  hyaline, 
being  of  a  deep-brown  color.  The  conidia  measure  from  18  to  36  by 
8  to  14  /*.  In  old  cultures  tufts  or  clusters  of  erect,  slender,  irregular, 
somewhat  branched,  hard,  black  bodies  5  to  15  millimeters  in  length 
are  formed  in  great  abundance,  covering  the  surface  of  the  culture 
(PL  V,  fig.  9).  These  appear  to  be  of  a  sclerotoid  nature.  They  have 
never  been  found  to  bear  fructifications  of  any  sort.  When  broken 
up  and  pieces  are  transferred  to  culture  media,  the  mycelium  grows 
and  soon  produces  conidia.  So  far  as  known  this  fungus  is  of  infre- 
quent occurrence  and  probably  causes  very  little  injury.  It  has  not 
been  found  in  a  fruiting  condition  upon  fruit  or  vines  in  the  field. 

Gloeosporium  minus  Shear.24 — Besides  the  Gloeosporium  (Glomer- 
ella  rufomaculans  vaccinii),  already  described  as  causing' the  cran- 
berry anthracnose,  another  has  been  found  which  has  been  published 
under  the  above  name.  Only  the  conidial  stage  is  known.  All 
efforts  to  produce  an  ascogenous  form  have  thus  far  failed. 

The  aceryuli  are  amphigenous,  small,  and  scattered,  and  do  not 
form  a  definite  discolored  spot  on  the  leaf  so  far  as  observed.  They 
sometimes  occur  upon  the  berries.  In  such  cases  the  epidermis  is 
dark  colored  above  and  about  the  acervulus.  The  conidia  are  dis- 
charged through  a  rupture  in  the  epidermis  and  form  a  pale  pinkish, 
glutinous  mass.  They  are  oblong-elliptical  or  subcylindric  and  some- 
times inequilateral  or  somewhat  clavate  (PL  III,  fig.  11),  and  are 
usually  guttulate  when  fresh.  They  vary  in  size  from  6  to  9  by 
3  to  4  p.  and  are  borne  on  simple,  slightly  tapering  sporophores  one 
and  a  half  to  two  times  the  length  of  the  conidia.  No  seta3  have  been 
observed  in  any  of  the  acervuli. 

The  conidia  of  this  species  are  only  about  one-half  as  large  as 
those  of  Glomerella  rufomaculans  vaccinii  and  show  no  great  amount 
of  variation,  either  under  natural  conditions  or  in  cultures.  This 
species  is  perhaps  closely  related  to  Gloeosporium  myrtilli  Allesch., 
which  has  conidia  6  to  10  by  1.5  to  3  /*,  and  occurs  on  Vaccinium 
myrtillum  in  Germany. 

This  fungus  wTas  first  found  on  cranberries  offered  for  sale  in  the 
Washington  market  in  April,  1902.  It  has  also  been  found  on 
cranberry  leaves  from  New  Jersey  and  has  been  isolated  from  other 
leaves  from  the  same  State.  It  is  apparently  of  comparatively  rare 
occurrence  and  perhaps  of  little  importance  as  a  disease  producer, 
no 


LESS    IMPORTANT    DISEASES.  41 

Sporonema  oxycocci  Shear.-4 — This  excipulaceous  fungus  has  been 
found  on  cranberry  leaves  from  various  localities.  The  pycnidia  are 
imperfectly  developed,  the  upper  portion  being  thin  and  disappearing 
toward  the  center  of  the  disk  (PL  V,  fig.  18).  They  are  dark  brown, 
scattered  or  gregarious,  pulvinate,  covered  by  the  epidermis,  and 
measure  about  50  to  100  ^  in  diameter.  They  rupture  by  a  longi- 
tudinal or  irregularly  triangular  slit  (PL  V,  fig.  17).  The  spores 
are  continuous,  hyaline,  cylindrical,  obtuse,  borne  on  very  short  ovoid 
sporophores,  and  measure  17  to  19  by  3  to  4  ^  (PL  V,  figs.  19  and  20). 
In  cultures  the  range  of  variation  in  spore  measurement  was  some- 
what greater,  being  15  to  20  by  3  to  4  /*. 

Specimens  have  been  obtained  from  Carver  and  on  Cape  Cod, 
Mass.,  and  Martinsville,  Me. ;  also  from  near  Belleplain  and  Whites- 
ville,  N.  J.,  the  dates  ranging  from  June  to  September. 

This  fungus  has  usually  been  found  on  dead  or  dying  cranberry 
leaves,  but  in  one  instance  it  was  found  in  a  diseased  berry  which  was 
obtained  in  the  Washington  market.  The  berry  had  a  soft,  slightly 
discolored  spot.  After  thoroughly  washing  and  soaking  the  berry 
in  corrosive  sublimate  solution,  a  portion  of  the  diseased  pulp  and 
skin  of  the  fruit  was  carefully  transferred  to  a  flask  of  sterilized 
corn  meal.  Normal  pycnidia  of  the  fungus  developed  upon  the 
portion  of  the  skin  of  the  berry  in  the  culture.  The  mycelium 
spread  to  the  culture  medium  and  formed  a  rather  compact  thin 
layer,  at  first  whitish,  then  dark  grayish  green,  and  finally  dark 
grayish  brown  and  somewhat  mouse  colored.  In  about  a  month 
mature  pycnidia  were  formed  about  the  sides  of  the  flask.  The  so- 
called  pycnidia  are  incomplete  and  consist  in  the  culture  of  dense, 
dark,  pulvinate  masses  depressed  at  the  center  where  the  pycnospores 
are  borne  and  somewhat  overgrown  by  loose  hyphse  from  about  the 
margin.  Frequently  instead  of  normal  spore  development  the  sporo- 
phores became  lengthened  and  formed  irregular  stout  hyaline  fila- 
ments about  twice  the  length  of  the  spore.  The  single  instance  in 
which  this  fungus  has  been  found  in  the  fruit  shows  that  while  it  is 
capable  of  injuring  the  fruit,  it  perhaps  does  very  little  damage  at 
present. 

Arachniotus  trachyspermus  Shear.23 — This  fungus  was  first  iso- 
lated from  a  very  badly  diseased  berry  from  New  Jersey  which  had 
been  kept  from  September  until  April  11.  The  berry  was  very  soft 
and  light  colored.  The  same  fungus  has  also  occurred  twice  on  the 
surface  of  decayed  fruit  which  had  been  kept  in  a  moist  chamber  for 
a  considerable  period. 

In  pure  cultures  the  fungus  first  forms  a  fine,  thin,  white  mycelium, 
which  is  soon  followed  by  the  development  of  minute  arachnoid 
snowy -white  perithecia  (PL  IV,  figs.  18  and  19),  which  are  325  to 
no 


42  CRANBERRY    DISEASES. 

425  fji  in  diameter  and  consist  of  slender,  thin-walled,  unarmed 
hyphaB,  forming  an  anastomosing  arachnoid  layer  about  the  mass  of 
asci.  The  asci  are  globose  or  subglobose,  very  thin  walled,  and  7  to 
8  p.  in  diameter  (PL  IV,  figs.  20  and  21).  The  ascospores  are  ovoid, 
light  lemon  yellow  in  mass,  echinulate-roughened,  and  measure  from 
3.25  to  4  by  2  to  2.5  /*  (PL  IV,  fig.  22).  The  asci  are  very  closely 
packed  together  and  borne  upon  the  tips  of  the  very  slender  and 
scantily  branched  filaments  of  the  ascogenous  hyphse.  It  is  not  until 
the  ascospores  are  fully  mature  that  the  color  and  rough  surface  are 
readily  recognized. 

The  species  is  closely  related  to  A.  candidus  (Eid.)  Schroet.,  but 
differs  in  having  rough,  faintly  colored  spores.  A  minute,  greenish, 
conidial  form  resembling  Penicillium  occurred  in  all  the  old  cultures 
of  this  fungus.  These  cultures  were  apparently  pure  and  free  from 
contamination,  and  it  seems  quite  probable  that  this  represents  the 
conidial  stage  of  this  Arachniotus.  We  have,  however,  been  unable 
as  yet  to  satisfactorily  demonstrate  this  by  other  cultures  made  from 
ascospores  and  conidia.  This  fungus  has  not  been  found  fruiting  in 
the  field,  and  is  probably  of  no  great  pathological  importance. 

Septoria  longispora  Shear.24 — This  fungus  has  been  collected  three 
times  in  New  Jersey — twice  upon  cranberry  leaves  and  once  upon  a 
fruit.  It  has  also  been  grown  in  ten  cases  in  cultures  from  cranberry 
leaves.  The  pycnidia  are  scattered  over  the  surface  of  the  leaf  or 
fruit  and  seated  beneath  the  epidermis.  They  vary  in  size  from  120 
to  250  p  in  diameter  (PL  IV,  figs.  12  and  13).  No  definite  spot  or 
discolored  area  seems  to  be 'formed.  The  pycnospores  are  very  long 
and  slender  and  curved,  varying  from  150  to  240  ^  by  3  to  4  /*  (PL 

IV,  fig.  14).     When  straightened  they  reach  300  /*  long.     They  are 
borne  on  simple  slender  sporophores  6  to  9  //,  long.    The  length  of  the 
spores  seems  to  separate  this  species  from  any  other  Septoria  de- 
scribed, as  they  are  twice  as  long  as  those  of  any  species  heretofore 
known.     This  fungus  appears  to  attack  the  fruit  but  rarely.     It  has 
been  found  only  in  New  Jersey,  and  is  apparently  of  infrequent 
occurrence. 

Sphaeronema  pomorum  Shear.24 — This  fungus  has  been  found  but 
once:  It  was  obtained  in  a  culture  made  by  the  transfer  of  hyphse 
from  the  interior  of  a  diseased  berry  taken  from  a  lot  of  sprayed  fruit 
from  New  Jersey.  It  has  been  kept  growing  on  culture  media  for  a 
long  time.  The  fungus  first  formed  a  thin  white  layer  upon  the 
culture  medium,  and  this  was  soon  followed  by  the  development  of 
numerous  pycnidia  quite  evenly  scattered  over  the  surface  of  the 
mycelial  layer,  giving  it  a  dark  appearance.  The  pycnidia  are 
membranous  or  subcoriaceous,  globose  or  subglobose,  120  to  200  p 
in  diameter,  and  provided  with  a  slender  neck  about  80  /*  long  (PL 

V,  fig.  1).    The  pycnospores  are  hyaline  or  pale  greenish  yellow  in 
no 


LESS    IMPORTANT    DISEASES.  4 

mass,  oblong  or  subcylindric,  and  measure  from  5  to  10  by  3  to  6  ^ 
(PL  V,  fig.  1,  «).  This  fungus  has  not  been  found  upon  either  leaves 
or  fruit  in  the  field,  and  appears  to  be  of  rather  rare  occurrence. 

Phyllosticta  putrefaciens  Shear.24 — This  fungus  has  been  obtained 
in  two  cases  in  cultures  made  from  the  hyphse  taken  from  the 
interior  of  decayed  berries.  The  berries  were  picked  from  the 
sprayed  plats  at  Whitesville,  N.  J.,  and  kept  in  the  laboratory  about 
a  month.  The  berries  showed  no  external  appearances  which  would 
indicate  that  the  disease  was  different  from  that  produced  by  rot  or 
scald  fungi. 

The  pycnidia  are  gregarious,  membranous,  globose,  or  subglobose, 
and  vary  from  75  to  150  //,  in  diameter  (PI.  V,  fig.  10).  The  spores 
are  faintly  yellowish  in  mass,  ovoid  or  oblong-ovoid,  and  measure 
from  4  to  6  by  2  to  3  /x  (PI.  V,  fig.  10,  a).  In  the  cultures  the  fungus 
first  produced  a  thin,  white,  floccose  mycelial  layer  over  the  surface  of 
the  medium.  This  gradually  became  thicker  and  then  produced  a 
layer  of  black  pycnidia.  What  appears  to  be  the  same  fungus  has 
been  found  on  leaves  from  Massachusetts.  A  fungus  closely  resem- 
bling this  one  has  also  been  collected  in  Massachusetts  on  cranberries 
which  had  been  destroyed  by  the  berry  worm.  The  spores  were 
slightly  larger  and  the  ostiole  different.  This  fungus  presumably  is 
the  pycnidial  stage  of  some  ascogenous  fungus,  but  no  such  form  has 
appeared  in  any  of  the  numerous  cultures  which  have  been  made. 

Anthostomella  destruens  Shear.24 — This  fungus  has  only  been 
found  in  one  instance,  when  it  was  obtained  from  a  diseased  berry 
grown  in  New  Jersey.  The  culture  was  made  November  2  by  trans- 
ferring the  fungous  hyphse  from  the  interior  of  the  berry,  as  in  the 
other  cases  mentioned.  A  white  mycelial  layer  was  first  formed,  and 
this  was  soon  followed  by  the  development  of  black  perithecia  more 
or  less  overgrown  by  the  white  filaments  of  the  mycelium.  The  peri- 
thecia are  membranous  or  submembranous,  globose,  and  350  to  450  //, 
in  diameter  (PI.  IV,  fig.  8).  The  asci  are  cylindric  or  cylindric- 
clavate  and  vary  from  150  to  225  by  14  to  18  ^  (PL  IV,  fig.  9).  No 
paraphyses  have  been  found.  The  ascospores  are  dark  brown,  ellip- 
tic, uniseriate,  and  16  to  24  by  10.5  to  12  /*  (PL  IV,  fig.  10).  This 
fungus  has  not  been  found  fruiting  in  the  field  and  is  apparently  of 
rare  occurrence.  None  of  the  cultures  made  from  ascospores  has 
shown  any  other  spore  form.  The  plant  is  perhaps  rather  closely 
related  to  Anthostomella  picacea  (C.  &  E.)  Sacc.,  which  has  been 
found  on  Vaccinium,  but  it  is  easily  separated  by  the  size  of  the  asci 
and  spores. 

Penicillium  glaucum  Link. — This  fungus  occurs  frequently  on  old 

diseased  fruit  when  it  is  kept  in  a  sterile  moist  chamber.     It  grows 

especially  upon  the  old  calyx  of  the  flower  and  the  apex  of  the  fruit 

and  has  been  isolated  from  the  pulp  of  decayed  fruit..  In  cultures  and 

no 


44  CRANBERRY   DISEASES. 

on  decaying  fruit  it  occasionally  produces  the  coremium  form.  The 
fungus  probably  does  not  cause  decay  of  the  fruit,  except  where  the 
skin  has  been  injured  to  permit  its  entrance. 

Leptothyrium  pomi  (Mont.)  Sacc.  ? — Occasionally  about  picking 
time  there  appear  on  cranberries  minute  black  fungous  specks  or 
spots  having  an  appearance  identical  with  that  of  the  "  fly  speck  " 
or  fruit  speck  of  the  apple.  Microscopical  examination  shows  that 
these  spots  consist  of  thin,  dense,  superficial,  dark-colored,  short- 
celled,  rather  thick-walled  hyphse.  When  old  the  spots  are  slightly 
convex,  and  when  examined  in  cross  section  show  a  somewhat  lighter 
colored  compact  cellular  mass  closely  attached  to  the  epidermis  of  the 
fruit  (PI.  V,  fig.  15).  Specimens  kept  for  a  long  time  in  a  moist 
•chamber  have  never  shown  any  indication  of  spore  formation.  A 
study  of  these  specks  in  different  stages  of  formation  shows  that  they 
arise  from  a  germinating  spore.  An  anastomosing,  dark-colored, 
thick- Availed  mycelium  is  formed  (PL  V,  figs.  13  and  14),  which 
continues  for  some  time  to  increase  in  size  and  thickness  until  it 
reaches  the  condition  shown  in  Plate  V,  figure  15.  A  careful  ex- 
amination of  the  surface  of  berries  bearing  these  specks  revealed 
the  presence  of  three  different  kinds  of  fungous  spores-  (PI.  V,  fig.  16, 
«,  &,  and  c).  Those  shown  at  ~b  and  c  were  rather  frequent.  The  form 
shown  at  a  is  the  only  one  which  was  found  germinating,  and  as 
remains  of  similar  spores  were  found  connected  with  the  very  young 
specks  we  are  led  to  think  that  they  are  produced  by  these  spores. 
We  have  no  means  of  knowing  to  what  genus  of  fungi  any  of  these 
spores  belong.  Those  shown  at  c  bear  a  strong  resemblance  to 
Cladosporium. 

So  far  as  we  have  been  able  to  learn,  no  one  in  this  country  has 
found  any  spores  produced  by  this  fungus.  We  have  attempted  to 
grow  the  plant  in  culture  media,  but  without  success.  Labrella  pomi 
Montagne 5G  was  described  as  follows :  "  Macula  nulla,  peritheciis 
ellipticis  minimis  rugosis  nitidis,  sporidiis  globosis."  In  view  of 
the  mention  of  globose  spores  in  the  description  and  our  scanty  knowl- 
edge of  the  original  plant,  it  is  rather  doubtful  whether  the  plant 
we  are  dealing  with  is  that  described  by  Montagne. 

This  fungus  has  only  been  seen  from  one  locality,  Parkdale,  N.  J. 
It  does  not  seem  to  injure  the  fruit  except  that  it  renders  it  unsightly. 
Thorough  spraying  will  probably  prevent  its  appearance. 

FUNGI   OCCURRING   ON   THE  LEAVES   OR   STEMS. 

Several  of  the  species  of  fungi  already  described  as  attacking  the 

fruit  are  also  found  on  leaves  or  stems.     The  following  species  have 

been  found  only  on  the  leaves  or  stems  of  the  cranberry.     So  far  as  our 

present  knowledge  of  these  goes,  they  do  not  cause  sufficient  injury 

no 


LESS    IMPORTANT    DISEASES.  45 

to  be  of  great  economic  importance.  Their  future  behavior  can  not 
be  foreseen,  however,  and  they  may  bear  some  direct  relation  to  each 
other  or  to  the  other  parasites  which  may  prove  important. 

Venturia  compacta  Peck.54 — This  fungus  has  been  before  reported 
upon  the  cranberry  by  Professor  Peck,  who  found  it  in  New  York. 
It  has  also  been  collected,  according  to  Ellis,  in  Maine,  and  by 
Halsted  in  northern  New  Jersey.  We  have  found  it  on  cranberry 
leaves  from  Nova  Scotia,  and  also  from  Massachusetts,  New  Jersey, 
and  Wisconsin.  Fusicladium  has  been  demonstrated  to  be  the  conidial 
stage  of  certain  species  of  Venturia,  but  no  such  conidial  form  has 
been  found  in  connection  with  this  species.  Cladosporium  oxycocci 
Shear  has  been  found  associated  with  it,  but  nothing  is  known  as  to 
the  relation  between  the  two  forms. 

This  fungus  shows  considerable  variability,  especially  in  the  group- 
ing of  the  perithecia  and  the  production  of  spines,  the  size  and  shape 
of  the  asci,  the  presence  or  absence  of  paraphyses,  and  the  arrange- 
ment of  the  spores.  The  perithecia  are  usually  aggregated  in  rather 
dense  clusters,  but  are  occasionally  solitary  (PL  IV,  fig.  1).  The 
spines  may  be  few  and  arranged  about  the  ostiole  or  more  numerous 
and  scattered  over  the  upper  half  of  the  perithecium  (PI.  IV,  figs. 
3  and  5).  They  vary  in  size  from  30  to  60  by  6  /x.  The  asci  are 
usually  swollen  at  the  lower  end  (PI.  IV,  fig.  6),  but  are  frequently 
cylindrical  (PI.  IV,  fig.  4).  They  vary  in  size  from  48  to  66  by 
9  to  12  ju,.  The  spores  are  very  constant  in  size  and  shape,  measuring 
14  to  18  by  4  to  6  //,.  It  was  at  .first  thought  that  the  extreme  forms 
might  be  separate  species,  but  a  study  of  more  material  shows  all 
sorts  of  intermediate  conditions.  Schweinitz  57  has  reported  Venturia 
cincinnata  Fr.  on  Vaccinium  macrocarpum  from  Pennsylvania.  An 
examination  of  Schweinitz's  specimen  indicates  that  jt  is  Venturia 
compacta  Pk.  Fries's  58  species  was  found  on  Vaccinium  oxycoccus, 
and  so  far  as  the  description  goes  scarcely  differs  from  our  plant, 
except  that  the  perithecia  are  said  to  be  solitary.  We  have  been 
unable  to  find  a  specimen  of  Fries's  species  in  his  herbarium,  and  it 
is  perhaps  doubtful  whether  the  two  species  are  the  same.  It  seems 
rather  probable,  however,  that  such  is  the  case. 

This  fungus  seems  to  be  comparatively  rare  except  in  Massachu- 
setts, and  though  a  parasite  it  evidently  does  little  damage.  It  is 
not  known  to  attack  anything  but  the  leaves.  However,  from  the 
habits  of  its  near  relatives,  which  cause  the  serious  scab  diseases  of 
other  fruits,  it  may  perhaps  sometimes  attack  the  fruit  of  the 
cranberry. 

Sclerotinia  oxycocci  Wor?9 — The  Monilia  form  of  a  fungus  closely 
resembling  this  was  found  upon  the  young  leaves  and  tips  of  cran- 
berry plants  sent  from  Wisconsin  in  July,  1905.  This  fungus  has 
no 


46  CRANBERRY    DISEASES. 

not  been  reported  heretofore  upon  the  American  cranberry,  though 
different  species  of  the  genus  attack  various  species  of  Vaccinium  in 
Europe  and  do  considerable  damage  to  the  fruit.  Under  favorable 
conditions  for  its  reproduction  and  distribution  this  fungus  might 
prove  a  very  serious  enemy  of  the  cranberry,  and  it  is  quite  important 
that  steps  should  be  immediately  taken  to  eradicate  it  whenever  and 
wherever  it  is  found. 

The  ascogenous  stage  of  this  fungus  has  not  yet  been  found  here, 
though  it  probably  occurs  in  the  locality  from  which  the  conidia 
were  obtained.  The  conidia  are  borne  in  chains  and  measure  12  to  20 
by  10  to  12  p  (PL  IV,  fig.  23).  They  agree  in  all  particulars  with 
Woronin's  description  and  figures,  except  in  the  size  of  the  spores. 
In  his  description  Woronin  gives  25  to  28  by  16  to  22  //,  as  the  meas- 
urements. 

Discosia  artocreas  (Tode)  Fr. — This  fungus  has  been  found  on 
cranberry  leaves  from  Cranmoor,  Wis.,  which  had  been  kept  in  the 
laboratory  in  a  moist  chamber.  Other  specimens  have  been  ob- 
tained on  leaves  from  near  Whites ville  and  Jamesburg,  N.  J.,  from 
Wareham  and  Brewster,  Mass.,  and  from  West  Virginia.  The  speci- 
mens collected  in  the  field  were  found  in  September  and  November. 
This  fungus  has  usually  been  regarded  as  a  saprophyte  and  probably 
does  no  particular  injury  to  the  cranberry  plant. 

Plagiorhabdus  oxycocci  Shear.24 — This  interesting  fungus,  which 
it  has  been  necessary  to  refer  to  a  new  genus  and  species,  was  found 
on  cranberry  leaves  collected  near  Carver,  Mass.,  in  May,  1906.  The 
pycnidia  are  scattered,  slightly  erumpent,  covered  by  the  epidermis, 
125  to  190  fj.  in  diameter.  The  wall  is  not  regular  and  well  developed, 
but  is  thicker  and  denser  above.  The  interior  is  either  simple  or 
somewhat  chambered,  but  opens  through  a  single  ostiole  (PL  V,  fig. 
2).  The  pycnospores  are  hyaline  or  faintly  colored  in  mass,  and 
are  borne  on  slender,  simple  sporophores  (PL  V,  fig.  3).  They 
measure  8  to  11  by  3  /x  and  are  borne  obliquely  on  the  sporophore, 
which  is  abstricted  at  its  base  and  remains  as  an  appendage  (PL  V, 
fig.  3,  «),  which  is  10  to  15  by  0.75  /*.  This  species  is  closely  related 
to  Plagiorhabdus  crataegi  Shear,24  which  is  found  on  the  fruit  of 
Crataegus.  It  would  therefore  not  be  surprising  if  the  species  occur- 
ring on  the  cranberry  should  also  be  found  upon  the  fruit. 

Sporonema  pulvinatum  Shear.24 — This  fungus  has  been  found 
upon  cranberry  leaves  in  three  instances — once  on  leaves  collected  in 
New  Jersey  in  November,  1905,  and  once  on  leaves  from  Olympia, 
Wash.,  collected  in  October;  also  upon  leaves  from  West  Virginia 
collected  in  June  and  kept  in  a  sterile  moist  chamber.  The  pycnidia 
are  simple,  dark  brown,  pulvinate,  formed  within  the  epidermis,  the 
outer  wall  of  which  adheres  to  their  surface.  They  are  300  to  420  /*, 
no 


LESS    IMPORTANT    DISEASES.  47 

in  diameter  Iby  100  to  150  //,  thick,  and  sometimes  collapse  from  above 
(PL  Y,  fig.  25).  No  signs  of  an  ostiole  have  been  seen,  and  the 
manner  in  which  the  pycnidium  ruptures  is  not  known.  The  spores 
are  pale  greenish  yellow  in  mass,  continuous,  subelliptical,  and  some- 
what curved,  6  to  8  by  2  to  2.5  /*.  They  are  borne  on  simple,  taper- 
ing sporophores  about  twice  the  length  of  the  spores  (PL  V,  figs.  27 
and  28).  The  pycnidia  bear  a  close  resemblance  to  immature  speci- 
mens of  Lophodermium  melaleucum  (Fr.)  De  Not.,  and  it  may  be 
the  pycnidial  stage  of  this  or  the  closely  related  Lophodermium 
oxycocci  (Fr.)  Karst.  This  fungus  is  closely  related  to  Sporonema 
epiphylliim  (Fr.)  Shear24,  but  has  larger  pycnidia  and  smaller 
spores,  which  are  less  curved  and  without  a  pseudoseptum. 

Rhabdospora  oxycocci  Shear.24 — This  fungus  has  been  found  on 
leaves  still  adhering  to  old  cut  vines  collected  in  September  and 
November  near  Whitesville,  N.  J.  The  pycnidia  are  formed  beneath 
the  epidermis  on  the  under  side  of  the  leaf  and  are  quite  evenly  dis- 
tributed over  its  surface.  They  are  depressed-globose,  slightly 
erumpent,  and  somewhat  cushion  shaped,  150  to  225  ^  in  diameter. 
The  wall  consists  of  two  layers,  wThich  sometimes  separate,  the  inner 
collapsing  and  expelling  the  spores  (PL  V,  figs.  21  and  22).  The 
ostiole  is  plain  or  slightly  depressed  and  the  epidermis  above  the 
pycnidia  is  blackened  and  transformed  by  the  fungus.  The  pycno- 
spores  are  hyaline,  narrow  cylindric-fusiform,  and  slightly  curved. 
They  show  one  or  two  septa  or  pseudosepta  at  maturity  and  measure 
20  to  26  by  2  to  3  //,.  The  sporophores  are  slender  and  branched 
(PL  V,  figs.  23  and  24).  This  fungus  has  not  yet  been  found 
attacking  the  berries. 

Leptothyrium  oxycocci  Shear.24 — This  fungus  has  been  collected 
several  times  on  living  and  dead  leaves.0  It  was  first  sent  from 
Pierceville,  Mass.,  by  Mr.  H.  J.  Franklin,  May  22,  1906.  The  pycni- 
dia are  dimidiate,  scattered,  irregular,  black,  erumpent,  subsuperfi- 
cial,  collapsing  and  rupturing  irregularly,  or  breaking  free  about  the 
base,  160  to  250  ^  in  diameter  (PL  V,  figs.  29  and  30).  The  wall  of 
the  pycnidium  shows  a  more  or  less  parallel  series  of  cells  in  its  struc- 
ture (PL  V,  fig.  31).  The  spores  are  hyaline,  fusiform-elliptic,  uni- 
septate,  10  to  15  by  2.5  to  3  p  and  borne  on  slender,  tapering  sporo- 
phores (PL  V,  figs.  32  and  33). 

Ceuthospora  (?)  lunata  Shear.24 — This  fungus  has  been  collected 
several  times  on  dead  and  dying  cranberry  leaves.  It  was  first  found 
by  the  writer  near  Wareham,  Mass.,  in  September,  1902.  It  has  also 
been  collected  at  Carver  and  Onset,  Mass.,  and  near  Whitesville,  N.  J. 
The  pycnidia  are  scattered,  depressed-pulvinate,  slightly  erumpent, 

ffl  Since  the  above  paragraph  was  written,  this  fungus  has  been  found  on  old 
mummied  fruit  at  the  same  place  where  the  other  specimens  were  collected. 
110 


48  CRANBERRY    DISEASES. 

200  to  375  //,  in  diameter,  irregularly  chambered  within  and  bearing 
a  single  prominent  ostiole,  through  which  all  the  chambers  empty 
(PL  V,  fig.  11).  The  walls  are  subcoriaceous  and  irregular  in  thick- 
ness. The  sporogenous  hyphae  form  a  dense,  compact,  intricate  layer, 
the  ultimate  divisions  of  which  are  somewhat  dichotomous  and  bear 
the  short,  elliptic,  inequilateral,  or  slightly  curved,  simple,  hyaline 
spores,  which  are  T  to  9  by  3  to  3.5  /x  (PL  V,  figs.  12  and  12,  a}. 

The  generic  relationship  of  this  fungus  is  rather  uncertain,  and 
we  have  referred  it  for  the  present  to  Ceuthospora,  though  it  does 
not  well  agree  with  the  description  of  the  genus. 

Valsa  delicatula  C.  &  E. — This  fungus  has  been  collected  at  Whites- 
ville,  N.  J.,  on  old  cranberry  stems  which  had  been  piled  at  the  edge 
of  a  bog.  It  also  occurs  on  other  ericaceous  plants  in  New  Jersey, 
but  has  not  heretofore  been  reported  upon  the  cranberry.  Associated 
with  the  ascogenous  perithecia  on  the  same  stems  was  found  a  Cyto- 
spora,  which  is  perhaps  the  pycnidial  condition  of  this  species. 

Cladosporium  oxycocci  Shear.24 — There  are  occasionally  found  in 
the  spring  on  leaves  of  the  previous  year  small,  brownish,  diseased 
spots  bearing  a  Cladosporium,  to  which  the  above  name  has  been 
given.  The  fertile  hyphse  are  brown,  septate,  more  or  less  flexuous, 
and  erect  or  spreading.  They  vary  from  50  to  100  /x  in  length  and 
arise  from  a  small,  black,  sclerotoid  base  (PL  IV,  fig.  24).  The 
conidia  are  acrogenous,  varying  from  ovoid  to  cylindric-clavate,  pale 
yellowish  brown,  continuous  or  uniseptate,  and  15  to  24  by  3  to  4  ^ 
(PL  IV,  fig.  24,  a}.  We  have  specimens  from  Arichat,  Nova  Scotia, 
from  Cape  Cod,  Massachusetts,  and  from  Belleplain,  N.  J. 

Another  Cladosporium  which  has  not  been  identified  specifically 
has  also  been  found  on  dead  tips  of  young  shoots  of  the  cranberry 
from  Massachusetts. 

Plectrothrix  globosa  Shear. — This  fungus  was  described  by  the 
writer  in  1902. 22  It  occurred  on  cranberry  leaves  which  were  kept  in  a 
sterile  moist  chamber  in  the  laboratory  and  was  quite  regularly  asso- 
ciated with  Pestalozzia  guepini  vaccinii,  making  its  appearance  soon 
after  the  maturity  of  that  fungus.  It  probably  has  no  genetic  rela- 
tion to  Pestalozzia,  however.  The  plant  has  not  been  collected  in 
the  field  and  is  perhaps  a  simple  saprophyte. 

Chondrioderma  simplex  Schroet. — This  myxomycetous  fungus  was 
found  at  Hampton,  N.  J.,  covering  living  cranberry  vines  and  other 
plants.  It  apparently  did  no  injury,  however,  except  such  as  might 
be  caused  by  temporarily  covering  the  surface  of  the  leaves  and 
vines.  The  sporangia  and  spore  masses  soon  rupture  and  disappear 
after  maturity  and  are  not  likely  to  do  any  permanent  damage  to  the 
plants, 
no 


PREVENTIVE    AND    REMEDIAL    MEASURES.  49 

Epicoccum. — An  undetermined  species  of  this  genus  was  obtained 
in  three  different  cultures  made  from  diseased  cranberry  vines  from 
Olympia,  Wash.  Whether  this  was  the  cause  of  the  diseased  condi- 
tion of  the  vine  is  not  known. 

Diplodia. — Dead  cranberry  vines  collected  at  Wareham,  Mass., 
and  near  Belleplain,  N.  J.,  bear  a  Diplodia  not  yet  satisfactorily 
identified.  The  spores  are  brown,  ujdseptate.  and  measure  14  to  18 
by  8  fi. 

Chaetomiiim. — One  or  two  species  of  this  genus  have  occurred  on 
leaves  kept  in  a  moist  chamber  and  also  in  cultures  made  from  cran- 
berry stems  and  berries.  In  some  cases  they  may  have  been  due  to 
contamination  and  in  any  event  are  probably  not  of  pathological 
importance. 

Oospora. — A  fungus  apparently  belonging  to  this  genus  has 
occurred  on  leaves  kept  in  a  moist  chamber. 

M acrosporium. — An  undetermined  species  of  this  genus  has  also 
been  found  in  cultures  and  on  leaves  kept  in  a  moist  chamber. 

PREVENTIVE    AND    REMEDIAL    MEASURES. 
REGULATION    OF   THE    WATER    SUPPLY. 

Careful  field  studies  have  indicated  beyond  doubt  that  the  physio- 
logical condition  of  the  plants,  as  well  as  their  environment,  has  much 
to  do  with  their  susceptibility  to  disease;  therefore, anything  which 
promotes  the  production  of  vigorous  and  hardy  plants  serves  as  a 
means  of  preventing  the  diseases  to  a  certain  extent.  It  is  difficult,  or 
impossible,  on  account  of  the  very  complex  factors  involved  in  the 
conditions  of  soil,  moisture,  and  the  plants  themselves,  to  tell  which 
are  of  most  importance  in  their  relation  to  the  occurrence  of  dis- 
eases. Certain  cranberry  bogs,  or  portions  of  bogs,  frequently  show 
much  more  loss  from  diseases  than  others.  From  the  experience  of 
various  growers,  as  well  as  from  our  own  observations,  it  appears 
that  the  control  of  the  water  supply  is  a  very  important  factor. 
The  quantity  of  water  necessary  to  keep  the  plants  in  the  most 
vigorous  condition  depends  largely  upon  the  nature  of  the  soil  and 
subsoil,  as  well  as  the  contour  and  natural  drainage  conditions  of 
the  land.  The  supply  of  water  should  be  constant  and  capable  of 
complete  control,  so  as  to  avoid  any  great  fluctuations  during  the 
growing  season.  In  order  to  accomplish  this,  the  water  supply 
should  be  obtained  from  a  reservoir  rather  than  directly  from  a 
running  stream.  Some  very  successful  growers  find  that  keeping 
the  water  at  such  a  level  in  the  ditches  that  the  surface  of  the  bog 

no 


50  CRANBERRY    DISEASES. 

will  be  continually  moist,  but  not  wet,  keeps  the  plants  in  the  most 
healthy  condition. 

DESTRUCTION   OF  DISEASED  VINES. 

It  is  also  important  that  steps  should  be  taken  so  far  as  practicable  to 
prevent  the  distribution  and  reproduction  of  the  diseases  by  destroy1 
ing  all  dead  vines  and  leaves  before  the  fungi  have  had  opportunity 
to  mature  and  set  free  their  spores.  Small  areas  of  vines  frequently 
die  from  the  attacks  of  fungi  and  from  other  causes.  All  such  vines 
should  be  pulled  or  cut  and  collected  early  in  the  season,  at  least 
within  a  week  after  the  water  has  been  drawn  from  the  vines,  and 
burned.  Vines  which  have  been  cut  in  raking  bogs  to  prepare  them 
for  scooping  should  also  be  destroyed  in  the  same  manner ;  otherwise 
the  spores  of  the  cranberry  fungi  develop  in  great  numbers  upon  them 
and  are  a  fertile  source  of  infection  for  the  young  leaves  and  fruit. 
Little  is  to  be  feared  from  full-grown  rotten  berries,  as  the  fungi 
very  rarely  produce  any  spores  upon  them. 

SELECTION    AND    BREEDING    OF    RESISTANT    PLANTS. 

The  selection  of  individual  plants  showing  ability  to  resist  the 
diseases  is  also  an  important  means  of  avoiding  them.  It  is  a  matter 
of  common  observation  that  some  of  the  varieties  are  much  more 
subject  to  disease  than  others.  It  may  also  be  noticed  that  in  any 
badly  diseased  area  of  vines  there  is  occasionally  one  Avhich  bears 
sound  fruit.  By  selecting  and  propagating  these  apparently  resist- 
ant plants  a  variety  much  less  subject  to  injury  could  probably  soon 
be  produced. 

APPLICATION    OF    FUNGICIDES. 

After  determining  the  life  histories  of  the  most  serious  parasites 
causing  the  diseases  it  seemed  very  probable,  judging  from  their 
relationships  and  the  manner  in  which  closely  related  species  attack 
other  fruits,  that  they  could  be  successfully  combated  by  the  applica- 
tion of  fungicides,  the  same  as  their  relatives  were.  Experiments 
and  tests  of  fungicides  have  been  conducted  for  the  past  four  years. 
Several  kinds  were  used  the  first  season,  as  already  mentioned.  Bor- 
deaux mixture  applied  in  the  form  of  a  spray  proved  much  more 
satisfactory  than  any  of  the  others.  Besides  these  a  dust  Bordeaux 
mixture  has  been  used  quite  thoroughly  by  one  of  the  cranberry 
growers,  but  without  any  decided  benefit, 
no 


PREVENTIVE    AND    REMEDIAL    MEASURES.  51 


HORDKAfX     MIX'li   III. 


In  the  spraying  experiments  plats  were  selected  where  from  75  to 
100  per  cent  of  the  crop  had  been  lost  by  disease  in  former  years. 
In  the-  experiments  of  1904  four  applications  of  Bordeaux  mixture 
were  made  during  the  season.  In  order  to  determine  accurately  the 
results,  alternate  plats  were  left  unsprayed,  as  a  check.  According 
to  actual  counts  of  the  sound  and  diseased  berries  made  at  picking 
time,  from  September  8  to  13,  on  35-yard-square  plats,  representing 
the  average  condition  of  the  sprayed  and  unsprayed  areas,  it  was 
found  that  the  greatest  percentage  of  diseased  fruit  on  any  of  the 
sprayed  plats  was  27.5,  as  against  100  per  cent  on  the  unsprayed  plats. 
The  minimum  amount  of  disease  on  any  of  the  sprayed  plats  was  13 
per  cent,  as  against  89  per  cent  on  the  check  plats.  The  average  num- 
ber of  diseased  berries  on  all  the  sprayed  plats  was  21.7  per  cent 
and  on  the  unsprayed  plats  76.8  per  cent,  and  in  addition  to  the  pro- 
tection of  the  fruit  from  diseases  the  general  vigor  and  appearance 
of  the  sprayed  plants  was  noticeably  improved. 

These  experiments,  owing  to  circumstances  beyond  our  control,  were 
not  entirely  satisfactory,  as  the  applications  of  the  fungicide  were 
not  made  with  sufficient  frequency  and  at  the  most  desirable  time. 
In  1905  a  more  thorough  and  satisfactory  series  of  experiments  was 
conducted  upon  the  same  plats.  The  wrater  was  removed  from  the 
bog  May  10  to  12.  It  is  the  usual  practice  of  cranberry  growers  to 
flood  the  bogs  from  twenty-four  to  thirty-six  hours  during  the  first 
week  in  June,  in  order  to  destroy  insects.  It  had  been  planned  to 
spray  part  -of  the  experimental  plats  before  this  second  flooding. 
The  water  supply  of  the  bog  was,  however,  insufficient  for  a  second 
flooding,  and  the  relation  of  spraying  to  this  operation  was  therefore 
not  determined.  Two  of  the  plats  were  sprayed  five  times — May  19, 
June  22,  July  14,  July  31,  and  August  15.  At  picking  time,  Sep- 
tember 8,  accurate  counts  were  made  of  all  the  diseased  and  sound 
berries  on  small  areas  which  showed  the  average  condition  of  the 
fruit  on  the  sprayed  plats.  Counts  were  also  made  on  equal  areas 
showing  the  average  condition  of  the  fruit  on  the  check  plats.  As  a 
result  of  these  counts  it  wTas  found  that  there  was  an  average  of  only 
0  per  cent  of  rotten  fruit  on  the  sprayed  plats,  while  there  was  a  little 
more  than  91  per  cent  rotten  on  the  unsprayed  plats.  TWTO  other  plats 
sprayed  five  times,  but  beginning  June  2  instead  of  May  19,  showed 
as  a  result  of  the  counts  made  as  in  the  experiment  just  mentioned 
an  average  of  2.30  per  cent  of  diseased  berries  on  the  sprayed  plats 
and  92.06  per  cent  of  diseased  fruit  on  the  unsprayed  plats.  This 
appears  to  indicate  that  the  application  made  on  June  2  was  more 
beneficial  than  that  made  at  the  earlier  date,  May  19. 
no 


52  CRANBERRY    DISEASES. 

Another  plat  was  sprayed  but  four  times,  as  follows :  July  14,  July 
31,  August  1,  and  August  15.  Estimates  of  the  amount  of  diseased 
fruit  on  the  sprayed  and  unsprayed  plats,  made  as  in  the  previous 
cases,  showed  18.3  per  cent  of  rotten  berries  on  the  sprayed  plat  and 
91.53  per  cent  on  the  unsprayed  plat.  This  indicated  what  had 
already  been  anticipated,  from  our  knowledge  of  the  time  of  ma- 
turity of  the  parasites  causing  the  diseases,  that  the  earlier  applications 
are  exceedingly  important,  most  of  the  infection  apparently  occurring 
before  the  fruit  is  half  grown. 

A  portion  consisting  of  1,048  square  feet  of  one  of  the  plats  which 
was  sprayed  five  times  was  carefully  hand  picked  and  produced  3 
bushels  of  sound  fruit,  this  being  at  the  rate  of  about  125  bushels 
per  acre.  The  same  area  from  the  adjoining  check  plat  gave  a 
scanty  peck  of  sound  fruit,  or  10.42  bushels  per  acre.  In  other  words, 
'there  was  twelve  times  as  much  sound  fruit  on  the  sprayed  plat  as  on 
the  unsprayed  plat,  or  a  saving  of  over  100  bushels  per  acre. 

Preparation  and  application. — The  method  of  preparation,  as  well 
as  the  dates  and  manner  of  application,  is  of  exceeding  importance 
in  securing  satisfactory  results.  The  Bordeaux  mixture  should  be 
freshly  made.  Good  stone  lime  should  be  used,  and  from  3  to  5 
pounds  of  commercial  resin-fishoil  soap  should  be  added  to  it.  In 
our  first  experiments,  in  which  the  plain  Bordeaux  mixture  was  used, 
it  was  found  that  the  spray  either  collected  in  drops  upon  the  surface 
of  the  leaves  and  fruit  or  ran  off  entirely,  the  surface  of  the  cran- 
berry leaves  and  fruit  being  so  glossy  that  the  mixture  did  not  spread 
and  adhere  properly.  It  was  found  that  by  adding  the- resin-fishoil 
soap  the  mixture  not  only  formed  a  film  and  spread  over  the  surface 
of  the  leaves  and  fruit,  but  also  adhered  for  a  much  longer  time  than 
the  plain  Bordeaux  mixture. 

The  comparison  of  sprayed  and  unsprayed  fruit  at  the  time  of 
picking  does  not  show  the  full  amount  of  profit  to  be  derived  from 
the  treatment,  as  there  is  usually  a  considerable  loss  from  the  develop- 
ment of  the  diseases  during  the  period  between  the  time  of  picking 
and  the  time  of  marketing  the  berries.  In  order  to  compare  the 
keeping  qualities  of  the  sprayed  and  unsprayed  fruit,  2,400  perfectly 
sound  berries,  so  far  as  could  be  determined  by  external  appearance, 
were  selected.  Twelve  hundred  berries  were  from  a  sprayed  plat  and 
1,200  from  a  check  plat.  They  were  all  kept  in  the  laboratory  under 
similar  conditions  in  order  to  determine  the  amount  of  disease  which 
would  develop  in  each  case  before  the  time  for  marketing  the  fruit. 
On  October  18,  the  date  upon  which  most  of  the  fruit  from  the  bog 
was  marketed,  and  exactly  one  month  from  the  date  of  picking,  a 
careful  examination  of  the  2,400  berries  showed  only  9.8  per  cent  of 
no 


SUMMAKY.  53 

the  sprayed  fruit  diseased,  while  138.1  per  cent  of  the  unsprayed  fruit 
was  diseased.  In  other  words,  four  times  as  much  of  the  unsprayed 
fruit  as  of  the  sprayed  fruit  decayed  between  the  time  of  picking  and 
marketing.  The  decay  which  developed  was  apparently  caused  by 
the  dormant  infection. 

Cost  of  spraying. — The  cost  of  spraying  as  it  was  done  in  these 
experiments  averaged -from  $15  to  $20  per  acre,  the  Bordeaux  mixture 
being  applied  at  the  rate  of  4  barrels,  or  200  gallons,  per  acre  at  each 
application,  making  for  five  applications  a  total  of  1,000  gallons  per 
acre.  The  cost  would  probably  vary  somewhat  under  different  condi- 
tions and  different  methods,  but  in  no  instance  should  it  exceed  $20 
per  acre. 

SUMMARY. 

There  are  four  serious  fungous  diseases  of  the  cranberry — scald, 
caused  by  Guignardi'a  caccinii;  rot,  caused  by  Acanthorhynchus  vac- 
cinii; anthracnose,  caused  by  Glomerella  rufomaculans  vaccinii,  and 
hypertrophy,  due  to  Exobasidium  oxycocci.  The  first  three  diseases 
mentioned  have  heretofore  been  confused  and  considered  as  one. 

Life  history  studies  have  shown  that  Guignardia  vaccinii  produces 
two  forms  of  fructification — pycnidial  and  ascogenous — and  is 
closely  related  to  Guignardia  bidwellii,  which  causes  the  black-rot  of 
the  grape. 

Similar  studies  of  Acanthorhynchus  vaccinii  reveal  only  ascogenous 
fructifications,  but  very  striking  and  characteristic  appressoria,  which 
perhaps  fill  in  part  the  place  of  a  pycnidial  form,  are  produced. 

Glomerella  rufomaculans  vaccinii  is  also  found  to  produce  both 
conidial  and  ascogenous  forms. 

The  production  of  ascogenous  fructifications  appears  to  depend  in 
both  Guignardia  raccinii  and  Glomerella  rufomaculans  vaccinii 
chiefly  upon  some  inherent  potentiality  of  the  race,  strain,  or  genera- 
tion from  which  the  hyphse  or  spore  used  in  the  culture  are  derived. 
The  composition  of  the  culture  medium  and  the  conditions  of  temper- 
ature, moisture,  and  light  are  relatively  unimportant  factors. 

The  fungi  producing  scald,  rot,  and  anthracnose,  as  well  as  Pesta- 
lozzia  guepini  vaccinii,  are  able  to  live  in  the  tissues  of  cranberry 
leaves  and  fruit  in  a  more  or  less  dormant  or  noninjurious  condition 
for  a  considerable  period  and  may  apparently  at  any  time  develop 
rapidly  and  destroy  the  tissues  when  conditions  are  favorable. 

Thirteen  other  fungi  have  been  found  affecting  cranberry  fruit, 
most  of  which  have,  however,  not  showrn  indication  of  particular 
pathological  importance.  Sixteen  different  species  have  been  found 
on  either  stems  or  leaves.  Most  of  these  do  not  seem  to  cause  serious 
injury  to  the  plant, 
no 


54  CRANBERRY    DISEASES. 

Preventive  measures  should  include  renovation  of  the  cranberry 
bog,  careful  control  of  the  water  supply,  and  the  cultivation  of  hardy 
and  disease-resistant  varieties. 

Thorough  treatment  with  Bordeaux  mixture  has  proved  successful 
in  controlling  the  diseases.  The  addition  of  resin-fishoil  soap  is 
essential  in  order  to  make  the  mixture  properly  cover  and  adhere  to 
the  plants.  As  a  result  of  five  applications  in  1905,  only  2.30  per  cent 
of  the  sprayed  fruit  was  found  to  be  destroyed  at  picking  time, 
whereas  92  per  cent  of  the  unsprayed  fruit  on  the  plat  a'd joining  was 
destroyed. 

The  cost  of  five  applications,  each  of  200  gallons  per  acre,  varies, 
according  to  the  conditions  and  methods  employed,  from  $15  to  $20 
per  acre, 
no 


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330,  1892. 

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16  SANDSTEN,  E.  P.,  HASKINS,  L.  P.,  and  RAMSEY,  H.  Preliminary  report  on  cran- 
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—  A    report    on    cranberry    investigations.     Wis.    Agr.    Expt.    Sta.,    119; 
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18  VIALA,  P.     Les  maladies  de  la  vigne.  ed.  3,  179  et  seq.,  1893. 
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20  BLAKESLEE,  A.  F.     Sexual  reproduction  of  the  Mucorinea3.     Proc.  Amer.  Acad. 

Sci.,  40 :  205-319,  1904. 

21  BREFELD,  OSCAR.     Untersuchungen  aus  dem  Gesammtgebiete  der  Mykologie,  10 : 

349,,  1891. 

22  SHEAR,  C.  L.     Mycological  notes  and  new  species.     Bui.  Torr.  Bot.  Club,  29 : 

449-457,  1902. 

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no 

55 


56  CRANBEEEY   DISEASES. 

24  SHEAR,  C.  L.     New  species  of  fungi.     Bui.  Torr.  But.  Club.  34:  305-317,  1907. 
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221,  1905. 
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Industry,  Bui.  100,  pt.  ],  1906. 

—  32d  Ann.  Meet.  Amer.  Cranberry  Growers'  Assn.,  8-11,  1902. 
Investigations  of  cranberry  diseases.     Proc.  33d  Ann.  Meet.  Amer.  Cran- 


berry Growers'  Ass.n.,  7-8,  1903. 

A  remedy  for  cranberry  scald.     Amer.  Agriculturist,  72 :  309,  1903. 

Report   on   cranberry   spraying   experiments.     Proc.    34th    Ann.    Meet. 


Amer.  Cranberry  Growers'  Assn.,  8-10,  Jan.,  1904. 

— 'Progress  of  cranberry  spraying  experiments.     Proc.   35th  Ann.   Conv. 
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Growers'  Assn.,  8-9,  Aug.,  1906. 
Cranberry   spraying   apparatus.     Proc.    37th   Ann.    Meet.    Amer.    Cran- 


berry Growers'  Assn.,  6-8,  Jan.,  1907. 

—  and   WOOD,    A.    K.      Ascogenous   forms    of   Gloeosporium    and    Colleto- 
trichurn.     Bot.  Gaz.,  43:  259-266,  1907. 

30  DUBELL,  E.  H.  Spraying  with  Bordeaux  mixture  for  cranberry  scald  finan- 
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3-6,  Jan.,  1907. 

37  FISCH,  C.     Beitrage  zur  Entwickelungsgeschichte  einiger  Ascomyceten.     Bot. 

Zeit,  40 :  851-870,  pis.  2,  1882. 

38  FRANK,   B.     Ueber    einige    neue    und     wenigbekanute    Pflanzenkrankheiten. 

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511-539,  pis.  3,  1883. 
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1888. 
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41  BUSGEN,  M.     Ueber  einige  Eigenschafter  der  Keimlinge  parasitischer   Pilze. 

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^  HASSELBRING,  HEINRICH.  Appressoria  of  the  anthracnoses.  Bot.  Gaz.,  42 : 
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42  ZOPF,    W.     Mechanik    der    Sporenentleerung    bei    Sordarieen.     Zeitschr.    fiir 

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44  GRIFFITHS,  DAVID.    The  North  American  Sordariacese.     Mem.  Torr.  Bot.  Club, 

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51,  1905. 
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110 


BIBLIOGRAPHY.  57 

so  SCOTT,  W.  M.,  and  QUAINTANCE,  A.  L.  Spraying  for  apple  diseases  and  the 
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110 


DESCRIPTION   OF  PLATES. 

PLATE  1. — Frontispiece.  Cranberry  scald,  showing  different  stages  in  the  prog- 
ress of  the  disease.  A. — Early  stage.  B. — Later  stage,  showing  dark  zones. 
C. — Berry  completely  destroyed. 

PLATE  II. — Fig.  1. — A  cranberry  leaf,  showing  pycnidia  of  Guignardia  vaccinii 
thickly  scattered  over  the  under  surface  ;  a,  a  cranberry  blossom  blasted  by 
Guignardia  vaccinii,  showing  pycnidia  on  calyx,  corolla,  and  pedicel;  7>,  a 
blasted  fruit,  showing  pycnidia.  Fig.  2. — A  vertical  section  of  a  single  pyc- 
nidium  of  Guignardia  vaccinii  from  a  cranberry  leaf,  showing  pycnospores 
in  various  stages  of  development.  Fig.  3. — An  immature  pycnospore  of 
the  same  fungus,  showing  the  partially  foruied  appendage ;  a,  the  same, 
showing  a  little  later  stage  of  development ;  It  and  c,  fully  developed  pyc- 
nospores and  appendages.  Figs.  4,  5,  6,  7,  8,  and  9. — Various  stages  in  the 
germination  and  growth  of  pycnospores  of  Guignardia  vaccinii  grown  in 
weak  sugar  solution ;  4,  5,  6,  and  7,  seventy-two  hours  after  sowing;  8  and  0, 
eighty-six  hours  after  sowing.  Fig.  10. — A  vertical  section  of  a  perithecium 
of  Guignardia  vaccinii,  showing  asci,  from  a  cranberry  leaf  collected  in  New 
Jersey.  Fig.  11. — Three  asci,  with  ascospores  showing  variations  in  length 
of  the  stipe  and  the  arrangement  of  the  spores ;  a  and  &,  from  perithecia  on 
a  leaf ;  c,  from  a  pure  culture.  Fig.  12. — A  fresh,  mature  ascospore,  show- 
ing the  usual  condition,  in  which  the  protoplasm  is  very  coarsely  granular. 
Fig.  13. — An  old  ascospore  from  a  dried  specimen,  having  its  contents  homo- 
geneous. Fig.  14. — a,  A  portion  of  the  coarse  brown  mycelium  from  the 
interior  of  a  scalded  berry,  from  which  a  culture  was  made  December  23, 
producing  pycnidia  and  ascogenous  perithecia  of  Gmgnardia  vaccinii ;  1),  a 
portion  of  younger,  lighter  colored  hypha?  from  the  same  berry.  Fig.  15. — 
Pestalozzia  gncpini  vaccinii ;  a,  a  conidium  having  an  apical  appendage  with 
three  branches ;  fr,  a  conidium  having  an  apical  appendage  with  four 
branches ;  o,  a  germinating  conidium ;  d,  a  germinating  conidium  sending 
out  two  germ  tubes. 

PLATE  III. — Fig.  1. — Vertical  section  through  an  acervulus  of  Glomcrella  rufo- 
maciilans  vaccinii  from  the  under  surface  of  a  cranberry  leaf.  Fig.  2. — 
Four  conidia  from  the  same,  showing  some  of  the  variations  in  form  and  size. 
Fig.  3. — A  portion  of  an  acervulus  of  Glomerella  rufomaeulans  vaccinii  from 
a  pure  culture  on  corn  meal,  showing  the  dark-colored  seta?  which  are  occa- 
sionally found;  a  and  &,  conidiophores  and  conidia  from  another  pure  cul- 
ture on  corn  meal.  The  conidiophores  arise  from  a  dark  stromatic  layer 
consisting  of  cells  resembling  appressoria,  as  shown  in  3,  a.  No  large  acer- 
vuli,  forming  dense  masses,  occurred  in  this  culture.  Fig.  4. — Appressoria 
or  chlamydospores  from  pulp  of  a  cranberry  from  Massachusetts  destroyed 
by  Glomcrella  rufomaeulans  vaccinii.  Fig.  5. — Portion  of  mycelium  from 
corn-meal  culture  No.  736,  forty-two  days  old.  Conidia  and  appressoria 
found,  fifteenth  day  ;  matured  asci  appeared  the  twenty-third  day — no  light 
spots  seen  in  these.  Where  they  appear  they  are  probably  due  to  the  presence 
of  vaeuoles  or  oil  globules.  Fig.  6.— An  ascogenous  perithecium  of  the  same 

no 
58 


DESCRIPTION    OF    PLATES.  59 

fungus  grown  in  a  pure  culture.  Fig  7.— Asci  from  the  same;  a,  cylindrical 
form,  with  overlapping  uniseriate  spores;  b,  shorter  subclavate  form;  c, 
ascus  from  older  culture,  showing  shorter  stipe.  Fig.  8. — Fresh,  mature 
ascospores  from  the  same.  Fig.  0. — Asci  and  fugaceous  paraphyses  from 
culture  of  Glonierella  rufotnaculans  vaccimi.  Fig.  10. — Portion  of  an 
acervulus  of  Gloeosporium  mi  mix,  from  a  pure  culture  from  a  diseased  New 
Jersey  berry.  Fig.  11. — Cornelia  from  the  same.  Fig.  12. — A  portion  of  a 
cranberry  leaf,  showing  the  slightly  elevated  epidermis  and  the  protruding 
neck  of  Acantliorhynclius  vaccinii.  Fig.  13. — A  single  perithecium  of  the 
same  fungus,  taken  from  a  pure  culture  on  corn  meal,  showing  portions  of 
the  hyphse  which  form  the  thin,  loose  mycelial  layer  writh  which  the  perithecia 
are  overgrown  in  artificial  cultures.  Fig.  14. — Asci  and  paraphyses  from 
the  same  pure  culture ;  a,  a  young  ascus,  in  which  the  mature  ascospores 
are  surrounded  by  granular  gelatinous  matter ;  ft,  a  slightly  older  stage ;  c, 
a  nearly  mature  ascus,  in  which  the  granular  protoplasm  is  shrunken  about 
the  spores  and  attached  to  the  apex  of  the  ascus.  A  portion  of  it  remains 
as  a  thin  gelatinous  envelope  about  the  spores  after  they  are  expelled  from 
the  ascus.  Fig.  15. — Two  aseospores  of  the  same.  Fig.  16. — A  germinating 
ascospore,  bearing  the  peculiar  appressorium.  Fig.  17. — An  appressorium 
viewed  from  above.  Fig.  18. — A  group  of  appressoria  attached  to  the  sur- 
face of  a  cranberry  leaf.  Fig.  19. — A  germinating  appressorium  grown  in  a 
poured  plate.  Fig.  20. — A  germinating  appressorium  from  the  midrib  of  a 
leaf,  showing  superficial  branching  hypha?.  Fig.  21. — A  section  of  a  germi- 
nating appressorium  on  a  leaf ;  a,  a  germ  tube  wrhich  has  entered  the  leaf 
through  a  stoma.  Fig.  22. — Another  germinating  appressorium ;  a,  the  germ 
tube  entering  the  leaf  through  a  stoma. 

PLATE  IV. — Fig.  1. — Ycnturia  compacta.  Massachusetts  specimens  on  the  under 
surface  of  a  leaf  showing  various  aggregations  of  perithecia.  (Natural 
size.)  Fig.  2. — Group  of  perithecia  magnified  24  diameters.  Fig.  3. — Single 
perithecium,  showing  spines  distributed  over  the  upper  half.  Fig.  4. — Two 
asci,  showing  variability  in  shape  and  length.  Fig.  5. — A  perithecium  of 
the  same  fungus  from  a  Wisconsin  specimen,  showing  fewer  spines  ar- 
ranged about  the  apex.  Fig.  6. — Three  asci  from  the  same,  showing  varia- 
tions in  shape  and  arrangement  of  the  spores.  Fig.  7. — A  single  ascospore 
from  the  same.  Fig.  8.— A  perithecium  of  Anthostomella  destruens  from  a 
pure  culture  of  the  fungus.  Fig.  9. — An  ascus  from  the  same.  Fig.  10. — 
Two  ascospores  of  the  same.  Fig.  11. — A  germinating  ascospore  of  Antho- 
stomella  destruens.  Fig.  12. — Pycnidia  of  Scptoria  longispora  on  under  sur- 
face of  a  cranberry  leaf.  Fig.  13. — Section  of  a  pycnidiuni  of  Septoria 
longispora  on  a  cranberry  leaf.  Fig.  14. — Three  spores  of  Septoria  longi- 
spora from  a  cranberry  leaf.  Fig.  15. — Synchytrium  vaccinii  on  pedicel, 
bracts,  and  flower  of  a  cranberry.  (Natural  size.)  Fig.  1C. — Synchytrium 
vaccinii.  A  single  gall  enlarged.  Fig.  17. — Synchytrium  vaccinii.  A  sec- 
tion through  a  gall  showing  the  hypertrophied  tissue  .and  the  sporocarp. 
Fig.  18. — Arachniotus  trachyspermus  on  a  decayed  and  shriveled  cranberry. 
Fig.  19. — Arachniotus  trachyspermus  on  the  side  of  a  culture  flask.  Fig. 
20. — Ascogenous  hypha?  and  asci  of  the  same  from  a  pure  culture.  Fig.  21. — 
A  single  ascus  of  the  same  from  a  pure  culture.  Fig.  22. — A  single  asco- 
spore of  the  same.  Fig.  23. — Rclerotinia  oxycocci  Wor?  Branching  chain 
of  conidia,  inverted ;  a,  a  single  conidium.  Fig.  24. — Cladosporium  oxy- 
cocci.  Conidiophores  bearing  conidia  from  a  cranberry  leaf;  a,  a  single 
septate  conidium  from  the  same. 

110 


60  CRANBERRY   DISEASES. 

PLATE  V. — Fig.  1. — 8phaeronema  ponioruin.  A  single  pycnidium  from  a  pure 
culture ;  a,  three  spores,  showing  variations  in  size  and  shape.  Fig.  2. — 
Plagiorhabdus  oxy cocci.  Vertical  section  of  a  pycnidium  on  a  cranberry 
leaf.  Fig.  3. — Plagiorhabdus  oxycocci,  sporophores  and  spores;  a,  three 
spores  with  basal  appendages  consisting  of  the  greater  part  of  the  abstricted 
sporophore.  Fig.  4. — Helminthosporium  inaequalis,  showing  fertile  hypliu* 
and  the  varied  arrangement  of  the  conidia.  Figs.  5,  6,  and  1. — Hclmintho- 
sporium  inaequalis.  Conidia  showing  variation  in  size,  shape,  and  septa- 
tion.  Fig.  8. — Helminthosporium  inaequalis.  A  strand  of  the  mycelium. 
Fig.  9. — Helminthosporium  inaequalis.  Erect,  branched,  black,  subcarbona- 
ceous  bodies  produced  in  old  cultures.  Fig.  10. — Phyllosticta  putrefaciens, 
from  a  culture.  Pycnidia  ;  a,  four  spores  from  the  pycnidia,  showing  varia- 
tions in  size  and  shape.  Fig.  11. — Ceuthospora  (?)  lunata  on  a  cranberry 
leaf,  showing  a  vertical  median  section  of  a  pycnidium.  Fig.  12. — Ceutho- 
spora (?)  lunata.  Sporogenous  hyphse  and  sporophores  as  seen  when 
crushed  out ;  a,  three  spores  showing  variations  in  size  and  shape.  Fig. 
13. — Leptothyrium  pomi  (?).  An  early  stage  in  the  formation  of  the 
"  speck."  The  remains  of  a  spore  from  which  it  seemed  to  have  arisen  are 
still  present.  Fig.  14. — Leptothyrium  pomi  (?).  An  older  condition.  Fig. 
15. — Leptothyrium  pomi  (?).  A  vertical  section  from  a  cranberry,  showing 
the  structure  of  the  interior.  No  signs  of  spore  production.  Fig.  16,  n,  I), 
c.. — Leptothyrium  pomi  (?).  Spores  found  associated  with  Leptothyrium 
pomi  on  the  surface  of  the  fruit ;  a,  a  germinating  spore  of  an  unknown 
fungus  from  which  some  specks  at  least  appeared  to  arise.  Fig.  17. — Sporo- 
nema  oxycocci.  Four  pycnidia  on  a  cranberry  leaf.  Fig.  18. — Sporonema 
oxycocci.  Vertical  section  from  a  cranberry  leaf.  Fig.  19. — Sporonema 
oxycocci.  Two  sporophores  with  nearly  mature  spores.  Fig.  20. — Sporo- 
nema  oxycocci.  A  single  spore.  Fig.  21. — Rhabdospora  oxycocci.  Section 
of  a  pycnidium  on  a  cranberry  leaf.  Fig.  22. — Rhabdospora  oxycocci.  Sec- 
tion of  a  pycnidium  from  a  leaf,  showing  the  inner  wall  separated  from  the 
outer  and  collapsed.  Fig.  23. — Rhabdospora  oxycocci.  Branched  sporo- 
phores with  young  spores.  Fig.  24. — Rhabdospora  oxycocci.  Another  viewT 
of  branched  sporophores  and  young  spores ;  a,  two  spores,  showing  pseudo- 
septa.  Fig.  25. — Sporonema  pulvinatum.  Two  pycnidia  on  a  cranberry  leaf. 
Fig.  26. — Sporonema  pulvinatum.  A  vertical  section  of  a  pycnidium.  Fig. 
27. — Sporonemq  pulvinatum.  Sporophores  and  young  spores.  Fig.  28. — 
Sporonema  pulvinatum.  Three  spores  showing  variations  in  size  and  shape. 
Fig.  29. — Leptothyrium  oxycocci.  Four  pycnidia  on  cranberry  leaf,  showing 
irregular  shapes.  The  one  in  the  foreground  has  broken  away  about  its 
base.  Fig.  30. — Leptothyrium  oxycocci.  Section  of  a  pycnidium,  showing  its 
dimidiate  character.  Fig.  31. — Leptothyrium  oxycocci.  Portion  of  the  wall 
of  the  pycnidium,  showing  the  parallel  arrangement  of  the  cells.  Fig.  32. — 
Leptothyrium  oxycocci.  Sporophores  and  spores.  Fig.  33. — Leptothyrium 
oxycocci.  Four  spores,  showing  the  variations  in  size  and  shape. 

PLATE  VI. — Cranberries  destroyed  by  blast  and  scald.  From  a  photograph. 
(Natural  size.) 

PLATE  VII. — Cranberry  Exobasidii.  A  and  B. — Exobasidium  vaccinii.  C  and 
D. — Exobasidium  oxycocci. 

110 


Bui.    110,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  II. 


FUNGOUS  PARASITES  OF  THE  CRANBERRY. 


Bui.    110,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


PLATE  III. 


FUNGOUS  PARASITES  OF  THE  CRANBERRY. 


Bui.    110,  Bureau  of  Plant  Industry,  u.  S.  Dept.  of  Agriculture. 


PLATE  IV 


FUNGOUS  PARASITES  OF  THE  CRANBERRY. 


PLATE  V. 


Bui.    110,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture. 


LESS  IMPORTANT  CRANBERRY  FUNQI. 


.V 


Bui.  1  10,  Bureau  of  Plant  Industry,  U.  S.  Dept.  of  Agriculture 


PLATE  VI. 


CRANBERRIES  DESTROYED  BY  BLAST  AND  SCALD. 

(Natural  size.) 


Bui.   1iO    Bureau  of  Plant  Industry,   U.    S.   Dept.   of  Agricultur 


PLATE  VII 


A.    HOEN    A    CO.,    LITH. 


CRANBERRY  EXOBASIDII. 


INDEX. 


Page. 

Acanthorhynchus  vaccinii,  appressoria 27-28 

ascogenous  form 27 

characteristics  of  the  fungus 27-30 

conidia  and  pycnidia  not  found 27 

cultures  of  the  fungus 29-30 

description -  12,27-30 

fruiting  specimens  collected .__         27 

relationship  of  the  fungus —  28-29 

treatment 30 

Anthostomella  destruens,  description -  14,43 

Anthracnose,  description,  etc -  12,30-35 

See  also  Glomerella  rufomaculans  vaccinii. 

Arachniotus  trachyspermus,  description  and  cultures 41-12 

Bibliography  of  cranberry  diseases -  55-57 

Blakeslee,  work  on  Mucor,  etc 20 

Blast  and  scald,  fungus  causing,  description,  etc ____  _  14-26 

or  blight,  description  and  history___ 12-13 

See  also  Guignardia  vaccinii. 

Blight,  or  blast,  blossom,  in  Wisconsin .  12r-13 

treatment  with  Bordeaux  mixture 13 

effect  of  fertilizers 13 

in  Wisconsin _ 12-13 

Bordeaux  mixture,  application  and  preparation 13,50-53 

formula  used 26 

results  of  spraying 25-26 

Brefeld,  views  as  to  ascus  formation 20 

Ceuthospora  (?)   lunata,  description -  47-48 

Chaetomium,  occurrence 49 

Chondrioderma  simplex,  occurrence 48 

Cladosporium  oxy cocci,  description  __.  48 

Copper  sulphate  applied  to  soil 24 

Copperas  applied  to  soil -  11,24 

Cranberry,  American 9 

cultivation,  effect 9 

period 9 

diseases,  where  most  serious__  '•> 

distribution 9 

fungi  heretofore  found 9 

scald.    See  Scald. 

susceptibility  to  diseases 9 

value  of  annual  crop 

Description  of  plates -  58-60 

61 


62  CRANBERRY    DISEASES. 

Page. 
Dlplodia,  occurrence 49 

Discosia  artocreas,  occurrence 46 

Diseases,  confusion  in  designation  by  growers 10 

description , 12-49 

distribution A 9 

history 9_12 

less  important 37—19 

loss,    annual 9 

more  important 12—37 

treatment,  preventive  and  remedial 49-54 

Epicoccum.  occurrence ; 49 

Exobasidium  oxycocci,  description,  etc 12,36-37 

relation  to  other  Exobasidii 36 

treatment 37 

vaccinii,  description 36 

Tungi  attacking  the  fruit,  descriptions 37-44 

occurring  on  the  leaves  or  stems,  descriptions 11  19 

Fungicides,  application .  50-53 

Bordeaux  mixture,  preparation,  application,  and  cost 50-53 

Gloeosporium  lindemuthianum,  appressoria,  or  chlamydospores 28 

minus,    description 40 

Glomerella  rufomaculans  vaccinii,  ascogenous  form 31-32,33 

fructification,  .production.         33 

appressoria,   or  chlamydospores 32 

conidial    form 31 

cultures 32-33 

description 12,31-35 

dormant  condition  of  the  fungus 34-35 

relationship  -of  the  fungus 33-34 

treatment 35 

Guignardia  bidwellii,  pycnidial  stage 15 

vaccinii,  acervuli,  development 30 

ascogenous  form,  description 15-16 

factors  determining  production 19-21 

conidial  form  not  found 19 

cultures 16-19 

producing  ascogenous    form 17-18 

pycnidial  form 16 

description,  etc 14-26 

dormant  condition  of  the  fungus 21-22 

fungus  causing  blast  and  scald,  description,  cultures, 

etc 13-26 

occurrence __r 12-13 

pycnidial   form,  description 14-15 

time  and  manner  of  infection 22-24 

treatment 24-26 

application  of  fungicides 25-26 

to  soil   of  lime,  plaster,  salt, 
sulphur,     copper     sulphate, 

and  iron  sulphate 11,24 

improvement  of  condition  of  plants 24-25 

selection  of  resistant  varieties 25 

110 


INDEX. . 


63 


Page. 

Halsted,  Byron  D.,  experiments 11,13 

Haskins,  experiments 12,13,14 

Helmintb&porttttQ  inaequalis,  description 39-40 

Hypertrophy,   description,   etc 12,35-37 

See  a/.vo  Exobasidium  oxycocci. 

Introduction  to  bulletin 9-10 

Investigations  of  diseases,  earlier 10-12 

Iron  sulphate  applied  to  soil 24 

Klebs,  experiments 19 

Leptothyrium  oxycocci,  description 47 

pomi.  description 44 

Less  important  diseases,  descriptions-, 37-49 

Lime  applied  to  soil 11,24 

Macrosporium,  occurrence: 49 

Malde,  experiments 12 

Most  serious  diseases 12-37 

New  Jersey  Experiment  Station,  cooperation 12 

Oospora,  occurrence 49 

Penicillium  glaucum,  description 43-44 

Pestalozzia  guepini,  description 39 

vaccinii,    description 38-39 

Hiyllosticta  putrefaciens,  description 43 

Plngiorhabdus  oxycocci,  description 46 

Plaster  applied  to  soil 24 

Plectroihr'ix  globosa,  description 48 

Prevention  of  diseases.     Sec  Treatment,  preventive  and  remedial. 

Ramsey,   experiments 13, 14 

Remedies.     See  Treatment,  preventive  and  remedial. 

Resistant  plants,  selection  and  breeding 50 

Rhabdospora  oxycocci,  description. _  47 

Roseliinia,  resemblance  to  cranberry  fungus. _  14 

Rot,  description 10,  26-30 

See  also  Acanthorhynchus  vaccinii. 

Salt  applied  to  soil ___  11,24 

Sandsten,  experiments 13, 14 

Scald,  acidity  in  soil  attributed  as  cause  of  disease 10 

burning  mummied  fruit  recommended 10 

description,  history,  treatment,  etc 10-26 

discussion  by  cranberry-growers'  associations 10 

diseases  covered  by  name 12 

distribution    15-16 

fungus  causing,  description,  etc _  14-26 

Taylor,  Thomas,  investigations  and  remedy  proposed 10, 11 

See  also  Guignardia  vaccinii. 

Schroeter,  suggestions  to  prevent  diseases 11 

Sclerotinia,  believed  by  Schroeter  to  be  cause  of  scald 11 

oxycocci,  believed  by  Woronin  to  be  cause  of  scald__  11 

occurrence ^ 45-46 

Septoria  longispora,  description 42 

(toil,  application  of  copper  sulphate  and  plaster 24 

copperas,  lime,  salt,  and  sulphur.-  _  11,24 

SpliM-roneiiia  pomorum,  description , 42-43 

110 


64  '   ^HA^TBEEKY    DISEASES. 


Page. 

Sporonerna  oxycocci,  description  _______________________________________  41 

pulvinaturn,  description  ___________________________________  46-47 

Spraying,  cost   ---------------------------------------------------  *___  53 

methods  and  results  _________________________________________  50-53 

Sulphur  applied  to  soil  ________________________________________________  11,  24 

Summary  of  bulletin  _________________________________________________  53-54 

Synchytrium  vaccinii,  description  ________________________  •  ______________  37-38 

Taylor,  Thomas,  investigation  of  cranberry  scald  _____  10 

treatment  of  soil  suggested  for  cranberry  scald  __________  24 

Thomas,  description  of  Synchytrium  vaccinii  ________  37 

Treatment,  Acanthorhynchus  vaccinii  __________________________   _______  30 

Exobasidium  oxycocci  ___________________  37 

Glomerella  rufomaculans  vaccinii  ___________________________  35 

Guignardia  vaccinii  _________________             ________________  24-25 

by  fungicides  ___________________________  25-26 

preventi  ve  and  remedial  _.                   _________________________  49-53 

application  of  fungicides  ______  .  _______  50-53 

Bordeaux  mixture,  cost  of  spraying,  53 
preparation     and 

application  ___  52-53 
results  of  experi- 

ments ________  51-52 

destruction  of  diseased  vines  _________  50 

selection    and    breeding    of    resistant 

plants  _________  50 

water  supply,  regulation  _____________  49-50 

scald,  Taylor's  remedy  _______  s  ______________________________  10 

Vaccinium  macrocarpum,  American  cranberry,  history  ___________________  9-10 

myrtillus,  disease  mentioned  by  Schroeter  ____________________  11 

oxycoccus,  native  cranberry  _________________________________  9 

Valsa  delicatula,  occurrence  ___________________________________________  '48 

Venturia  compacta,  description  ____________  _  ___________________________  45 

Vines,  diseased,  destruction  ___________________________________________  50 

Water  supply,  regulation  __________  ___________________________________  49-50 

White,  J.  J.,  paper  regarding  scald  ___________  10 

Whitson,  experiments  ____  _________________  12,13,14 

Woronin,  suggestion  as  to  treatment  of  cranberry  disease  ________________  11 

110 

O 


